Technical Specifications

  1. RMI-25
    1. RMI-25 Info
    2. RMI-25 in Racing Applications
    3. RMI-25 in Heavy Duty Equipment
    4. RMI-25 Benefits
  2. Electrolysis
  3. Cooling System
    1. Coolants
    2. Cooling System Info
    3. Cooling System Maintenance

RMI-25 Info

The recommended time interval for adding RMI-25 to the cooling system is 300 hours or 15,000 miles/yearly, whichever comes first. At that time, either retreat or test for pH and follow the procedures below. 2.RMI-25 does not contain any harmful solids such as silicates, nitrates, borates or molybdates. Therefore, standard test materials (nitrite strips, etc.) are not appli-cable. You do however need to periodically check for the freezing protection of the Ethylene Glycol with a Hydrometer. 3.RMI-25 does not build up in the system and should be re-dosed at the recommended ratio of 8 oz. per 5 gallons of coolant at each interval, or whenever either of the following conditions exist:

(a)pH Test: pH of the cooling system should be 8.5 to 10 (alkaline) pH. This can be determined by dipping a standard Hot Tub type test strip into the coolant (which will also do the tests for Alkalinity), or you can use standard full range litmus paper for pH only. Immediately compare the color of the paper to the color chart provided with the litmus paper. If the color chart indicates a pH below 8, re-dose the system with RMI-25. When pH of the system drops into the acid range (below 7) electrolysis can occur. A system that becomes prematurely acidic may have exhaust gases leaking into the system. Test strips or litmus paper is available at pool supply stores, chemical or laboratory supply stores, or carpet cleaning supply stores. Note: the accuracy of test strips declines rapidly with age (usually after about six months). The pH testing alone will typically tell you what you need to know, but as a double checking method, separate checking for Alkalinity may be preferred. If combined pH/Alkaline test strips are not used, the procedure shown next is recommended.

(b)Voltage/Ohm Meter Test: An untreated or worn out coolant has the characteristics of a battery. You can use the lowest DC voltage scale on a voltmeter. Drop the negative lead into the coolant and ground the positive lead. The surge at the moment of grounding is the proper reading to observe, as the current will quickly drain off reducing your voltage reading. With this method, the reading on a hot engine will be 4 or 5 times greater than on a cold engine. The reading on a cold engine should be multiplied by a factor of 4. If this value approaches ½ volt or 5/10ths, re-dosing is recommended. RMI-25 is a cleaner as well as an inhibitor and a lubricant. Even if a cooling system is let go a little too long, it will eliminate rust spots or water scale before laying down a new metal protecting film. RMI-25 will emulsify rust and corrosion and make it harmless.

RMI-25 in Racing Applications

RMI-25 Cooling System Treatment has been used in racing of all types.

  • Many tracks do not think very highly of crashes which may occur resulting in the spewing of a highly toxic contaminated anti-freeze coolant mixture on the raceway.
  • The only time ethylene glycol (anti-freeze) should be considered is when there might be a danger of extremely cold weather which may damage the engine.
  • Most racing situations do not even need the freeze protection of anti-freeze at all!
  • Since it is non-toxic and bio-degradeable, it can be used in the cooling systems of virtually every type of racing vehicle, and should be used in situations where there is a potential of damaging sensitive ecological environments……such as rally off-road racing.
  • Anti-freeze actually reduces water’s natural ability to act as a coolant……that’s why most anti-freeze mixes call for 50/50 with water, anything over that reduces the cooling system’s efficiency!
  • One of the ingredients in the formulation is a “surfactant.” Surfactants are more commonly referred to as “Water Wetters.”
  • Other components include rust and oxidation inhibitors which protect the system from deposits which would attack the system.
  • Also works great when using with antifreeze – it keeps the entire cooling system clean reducing the possibility of hot-spots in the engine.
  • Compatible with any ethylene glycol antifreeze.

We have many racing classes who have used, and continue to use the product, a few of these are: Sprint Cars, Drag Cars, Stock Cars, and various SCCA cars. They do not use anti-freeze unless in a climate which the temperatures drop down below freezing. Compared to the “other” leading brand of cooling system treatment, RMI-25 just plain out performs it, and it is non-toxic and bio-degradeable…….just look at the labels of other products, including those which are branded store labels and see for yourself! “If it is water cooled, it needs RMI-25!”

RMI-25 in Heavy Duty Equipment

Instructions for changing over from supplemental coolant additives in heavy duty trucks and equipment utilizing water filters One of the advantages of using RMI-25 Cooling System Treatment is that it is so simple and easy to use. For applications calling for the use of water filters in diesel trucks and equipment, it takes the guesswork out of doing it right, or in other words “which pre-charged filter do I use?” The answer is “none of them!” With RMI-25, you have everything you need in the container, most cases in one bottle. During your normal service interval, which should be every 15,000 miles or 300 hours, whichever comes first, simply replace the water filter with a new, uncharged filter and add the proper amount (8-ounces per 5 gallons of capacity) of RMI-25 to replace any additives which may have worn out. If you prefer to test the system for ph, you can do so with ph test strips; if the reading is acidic, you need to add RMI-25 to the system. You should ideally maintain an 8.2 to a 10.0 reading, which is in the neutral range. You cannot over-treat RMI-25, so there is no danger of creating damage to the system like the other SCAs on the market can! Once you have performed this procedure and have incorporated it into your main-tenance program, you are protected for the next 15,000 miles/300 hours of service….and, you get the extra protection of keeping the system clean, something no other product that we know of does! Using RMI-25 is so incredibly simple…..just “pour it in and drive away!”

RMI-25 Benefits


In terms of economics; It is a total pour in/drive-away system which extends antifreeze life, extends oil life, extends water filter life and has no disposal costs when used with water* only. There is no down-time, just pour it in and drive away! These features combine to make RMI-25 a very COST-SAVING, economical cooling system product which works while you drive. With proper scheduled maintenance, because of heat control, the engine and automatic transmission life will also be extended for an even greater return on your investment.


    *When using plain water, always make sure to use distilled or mineral-free water.

Major 25 Reasons for Heating Problems

  1. Mineral scale build up in radiator, cooling jackets and block
  2. Non-sealing radiator cap
  3. Hose leaks
  4. Radiator exterior plugged (debris, paper, leaves, dirt, etc)
  5. Engine timing
  6. Overloading
  7. High altitude
  8. Slipping fan belt
  9. inoperative fan belt
  10. Fan clutch
  11. Water pump impeller deterioration
  12. Thermostat malfunction
  13. Head gasket leak
  14. Transmission cooler
  15. Malfunctioning transmission
  16. Catalytic converter
  17. Restricted exhaust system
  18. Lack of attention to coolant level, or low coolant
  19. Surge tank (overflow dry)
  20. Overdosed antifreeze mix
  21. Improper dosage of mixing chemicals in coolant
  22. Restricted air flow
  23. Towing heavy loads
  24. Lean, starved fuel & air burn
  25. Air conditioning and comfort features
  • Air conditioning can add 15ºF
  • Power steering can add 10ºF
  • Emission controls can add 20ºF
  • Automatic transmission will create as much as 15ºF temperature rise
  • creating as much as 60ºF temperature rise and demanding more from the coolant


What is Electrolysis?
In simple terms, electrolysis in a radiator or heater is the localized degradation of the metal caused by excess electrical current flowing through lines in search of an electrical ground. But what happens when there is no ground to be found, or an ungrounded electrical device in the vehicle creates excess electrical current? Electrical current can be introduced in to the cooling system in many ways, but some common causes are loss of ground due to mechanical damage or corrosion, or a frayed wire in contact with the radiator. Any vehicle with accessories using the radiator support as a ground is begging for electrolysis.

Why haven’t I heard of Electrolysis?
Before the days of front-wheel drive and transverse-mounted engines, cooling system electrolysis was a rare occurrence. But today, with most cars and many light-duty trucks featuring electric cooling fans in conjunction with ungrounded plastic-tank radiators, cooling system electrolysis is becoming a frequent problem. Whether factory installed or aftermarket add-ons, electric motors, sensors, and task-specific microprocessors are packed into today’s cars, vans, pickups and SUVs. While the gadgets are interesting, if not always practical, they have greatly complicated the task of diagnosing and repairing today’s vehicles. In fact, the proliferation of electronic gadgetry, under the hood as well as under the dash, has triggered a whole new set of vehicle problems and diagnostic challenges. Besides attacking radiators and heaters, electrolysis can be a fast-acting menace that reportedly has destroyed an entire engine in a mere 20,000 miles due to reactions between the coolant and cooling system metals. A small amount of measurable voltage can be detected in most engine cooling systems. The detected voltage should never exceed a tenth (.10) of a volt in vehicles equipped with aluminum engine blocks and/or cylinder heads. Cast iron engines and cooling system components can tolerate higher stray voltages, perhaps as much as three-tenths (.30) of a volt. But that doesn’t mean that three-tenths is acceptable, it’s not.

What causes Electrolysis?
In cases of electrolysis, a defective or missing ground on an electrical device causes the electricity to seek the path of least resistance whenever the device is turned on. Sometimes the path of least resistance is coolant in the radiator or heater hose, or the radiator or heater itself. As the electrical current drawn by the poorly grounded accessory increases, so does the destructiveness of electrolysis. It has been reported that a poorly grounded engine and starter motor can zap enough current through the cooling system to damage a heater or radiator in a matter of weeks, depending on how often the vehicle is started. A partially grounded electric cooling fan, on the other hand, may only shoot a small percentage of its supply current through a cooling system, and the cumulative damage may take months or even years to reveal itself. It has also been proven that coolant flowing through dissimilar metals in the cooling system increases the incidence of “production” of electrical current as it goes through the system. Components which have aluminum and stainless steel which have coolant going through them are such examples. Evidence of electrolysis includes unexplained and/or recurring pinhole leaks in a radiator or heater. Pinholes may form anywhere along the tubes or tank walls. Damage is often concentrated at tube-to-header joints. Some industry professionals have even reported problems in the tube walls near the center of the core, where the electric cooling fan mounts come in contact with the radiator core.

How fast can Electrolysis work?
Industry sources tell us of one case where electrolysis completely destroyed a brand new aluminum radiator in less than 30 days. Aluminum affected by electrolysis can corrode rapidly in the form of flakes. These flakes will suspend in the cooling system and eventually build up causing system failure. Cast iron engine components can corrode, causing rust or scale to form, contaminating the coolant and allowing the system to slowly destroy itself. Premature part failures, overheating, and deposit formations are some common symptoms of electrolysis or are caused by electrolysis.

How is Electrolysis detected?
Testing for electrolysis in the cooling system is simple. A volt/ohmmeter measures the voltage or electric charge flowing through the coolant. Any voltage reading over .10 (tenth) indicates the possible presence of excess electrical current. Connect the black or ground lead to the battery ground and lower the red or positive lead into the coolant in the radiator. Do not touch the filler neck sides or the tank. Any reading over .3 voltage is indicative of excess current entering the cooling system. Always perform this test twice, once with the engine off and all accessories off and once with the engine running and common accessories (radio, heater or A/C, lights, etc.) on. If a spike occurs with all accessories turned on, you can usually determine where the ground fault is by turning them all off and then turning them on one by one. Once the source of the electrical problem has been identified, and steps have been taken to repair or replace the defective ground, be sure that your cooling system is flushed and the coolant replaced. Electrolysis destroys the corrosion protection of coolant and often produces chemical precipitates, which can plug the cooling system or cause damage by abrasion. The use of distilled water with the proper coolant and mix ratio is critical to the longevity of the radiator. In addition to electrolysis testing, pH levels should also be tested on a regular basis. Newer systems are more acidic and the need for higher pH reserves is essential. In the past, pH would read safe at around 7.5 to 8.0, but now it is more recommended to be between 8.5 to 10.0. RMI-25 Cooling System Treatment has been shown to be an effective deterrent used to help control electrolysis. It’s a complete cooling system treatment which protects against rust, corrosion, cavitation and low pH readings. Test for pH with a test strip and treat, or add 8 ounces per 5 gallons of coolant every 15,000 mi / 300 hrs for best results. It is the only product on the market which can be used with standard, or long-life coolants and the only product we know of which contains an effective cleaner to keep the entire system operating cool & trouble free. It is highly recommended for vehicles which do not use anti-freeze as it gives full protection, except for freezing. As one race car owner/driver recently said: “no more rust since we have started using it!”


Cooling Systems are an important aspect of engine life. This topic is hardly discussed and is often overlooked, we thought it has been a subject long worth commenting about………by Radiator Masters, Inc. If you listen to the manufacturers of long life coolants, they would want you to believe that it is light years ahead of the old green stuff. Hmmm…..I’m not ready to say that. The reason is that long life coolant (LLC) has been out for quite a few years, in fact it has been a decade already and people are still having problems with it,

Confusion is the ploy
In my estimation, the manufacturers of LLCs and the automotive manufacturers have done a good job of confusing everyone with all of the different colors and misinformation that’s floating around out there. Some brands like GM’s Dexcool don’t want anything else (supplemental additives) in the system. Most heavy duty brands tell you they have no Sodium Silicates or Nitrates/Nitrites or any toxic things in them. However, if you want it to last 600,000 miles you have to add those toxic extenders at the end of 300,000 miles as well as re-charging the system at the regular 10,000 to 12,000 mile service intervals in order for it to go another 300,000. So it seems that it’s more of a marketing ploy which enables the manufacturer to say things like they don’t have anything in them which can cause silicate drop out. The new LLCs or the extended life coolants (ELCs) depends on what you want to call them, just causes more confusion! The manufacturers have done a good job of keeping the confusion going and they don’t really want you to know anything about the cooling system because poor cooling system maintenance is the cause of a lot of engine problems

Complacency in maintenance abounds
Elizabeth Nelson, the Coolant Program Manager with Polaris Laboratories a fluid testing service in Indiana says LLC can reduce maintenance, BUT they do not eliminate it! The danger is that fleet managers are getting more and more complacent about maintenance when Long Life Coolants are used; in fact the perception is that we put it in and forget about it, until we get to 300,000 miles. She went on to say “that in general, many truck users ignore the cooling system but local fleets are worse than over the road operators. It’s a struggle to get the trucking industry to pay more attention to the engine’s cooling system, to the products they use and how to maintain it.” Most LLCs and ELCs are very explicit in their instructions on how to use supplemental coolant additives (SCAs) in trucking and heavy duty equipment applications. To follow that statement, most equipment service managers or technicians do not follow the instructions provided to insure that the proper protection is accomplished! The most common infraction of these is the fact that the incorrect charge water filter is installed at the time of service. This can lead to serious cooling system damage. In order to extend the life of LLCs and ELCs, it is necessary to periodically go through a cleaning procedure using highly toxic chemicals and is very time consuming. Do you suppose that very many are using this required maintenance procedure?…’s doubtful.

Keeping your system clean
The long life coolants won’t do any cleaning. No one talks about the importance of cleaning. The cooling systems of yesterday and today’s cars and trucks needed to be cleaned (and kept clean) and the systems of the cars and trucks of the near future are going to need to be cleaned on an ongoing basis. The best product, as well as the easiest to use in our estimation to accomplish this is RMI-25 Cooling System Treatment. It is needed more than ever with the hotter running engines, especially the ones with the low emissions technology.

Air is the biggest culprit
It’s pretty hard to keep air from entering a cooling system as time goes by. Often, things can loosen up and you can get a leak in a head gasket, which can let combustion gases into the coolant. This condition will quickly degrade any type of coolant, even Long Life Coolant. Overflow tanks are made to let air burp out of the system and not let it back in. It allows for expansion of the coolant. But if you let the coolant level get past the lowest level mark on the tank, air will be pulled into the radiator upon cooling and then you have opened up a foothold for corrosion to form in the system. With some truck manufacturers, there is no overflow tank. Systems with expansion tanks that leave an air void in the top of the radiator to catch expelled coolant can result in getting corrosion in the engine even with long life coolant! And people wonder how did that happen?

Low emissions = high heat
Brian Etchells, Research Manager in the commercial vehicle group at J.D. Powers said “that a decline in engine satisfaction could be attributed to the introduction of the NEW LOW EMISSIONS technology engines in both the heavy and medium–duty markets; we’ve seen a marked increase in engine problems and decline in engine satisfaction with engine performance. New, Low Emissions technology makes engines run hotter than they do without this technology, putting a big demand on a cooling system that’s barely adequate to begin with.” All the more reason to use a product such as RMI-25 and make sure the systems stays clean and in optimum condition.

Cutting corners costs money
A spokesperson for Chevron was quoted saying “don’t cut corners, if you do, the high temperatures are going to cost you DOWN TIME. Operators who continue to ignore, or treat the cooling system poorly will have problems that they could have gotten away with in the past.” About the only corner that the majority of the trucking and auto industries have been cutting is the CLEANING aspect of cooling system maintenance.

The best solution
RMI-25 Cooling System Treatment is such an easy product to use because you get the cleaning whether you need it or not and then it protects after it has cleaned the metal. Rust and corrosion cannot sneak up on you like it can with the typical sodium nitrate borate type inhibitors. Let’s face it, corrosion and mineral deposits can happen even with long life coolant according to the experts……..but not if you use RMI-25 Cooling System Treatment. It cleans, protects, lubricates, inhibits, prevents cavitation and electrolysis, it also has a “water-wetter” additive which makes water a better coolant, combine those and include an oxygen scavenger and even a black light leak detector for an efficient formula to “keep it cool” at a surprisingly low cost. RMI-25 Cooling System Treatment does no harm when added to anti-freeze, whether it is the old “green stuff” or the Long Life Coolants, as it does not contain Silicates, Nitrates, Borates or Molybdenates in the formula; those are the chemicals which the anti-freeze manufacturers do not want to see added to their products. No dangerous chemicals to use and in its original form it is non-hazardous, non-toxic and bio-degradable. In certain applications where freezing is not a concern, using RMI-25 with distilled water is all you need, thus you can eliminate the high cost of anti-freeze. Simply add 8 ounces of RMI-25 for every 5 gallons of coolant capacity in the system and re-charge it every 15,000 miles or 300 hours for optimum efficiency. The capacities for most cars and light pick-ups is 5 gallons, diesel pick-ups and medium duty trucks can be 7-1/2 to 10 gallons, and the larger diesels are mostly 20 gallons, some even more, refer to the owner’s manual to be certain. RMI-25 Cooling System Treatment is recommended for all types of water cooled engines, whether gas, diesel, stationary, marine or other applications. Need more information? Contact your RMI-25 distributor or check our website: So….. how good are they? LLCs & ELCs can be beneficial providing you “treat them right!”

Cooling System Info

An engine-mounted coolant sensor monitors the temperature of the coolant. The sensor’s resistance changes as the temperature goes up. The sensor’s output voltage may be used to operate a temperature gauge or warning light, the cooling fan and various emission functions. It is also used by the engine computer to determine when the engine can go into “closed loop” operation (when the computer uses input from the oxygen sensor to regulate the fuel mixture.) A defective sensor can prevent the engine from going into closed loop, cause poor fuel economy and cause higher emissions.

The cooling system’s job is to manage heat produced by the engine, to help the engine maintain warm up quickly and maintain a consistent operating temperature, and to provide heat for the heater.

The coolant is a mixture of water and antifreeze that circulates inside the engine and radiator. There are two basic types of antifreeze: ethylene glycol (EG), which is the most common, and propylene glycol (PG), which is less toxic to animals. Antifreeze is usually mixed in equal parts (50/50 mix) with water. With EG antifreeze, this provides freezing protection down to -34 degrees F and boilover protection up to 265 degrees F with a 15 psi radiator cap. Coolant needs to be changed periodically to renew the chemical additives that protect the cooling system against corrosion. The recommended change interval for traditional antifreeze (green and yellow) is two years/30,000 miles, and for the long-life coolants it’s five years/150,000 miles. Since 1996, General Motors has used a long-life coolant called Dex-Cool that is dyed orange. Long-life antifreeze and ordinary antifreeze should not be intermixed, as doing so will shorten the service life of the long-life antifreeze to ordinary antifreeze. Rust, scale and sediment can be removed from a cooling system by using a chemical cleaner and reverse flushing the system when the coolant is changed. Leaks can be prevented and small leaks sealed by using a sealer additive.

The thermostat regulates engine operating temperature. It is usually located in a housing where the upper radiator hose attaches to the engine. The thermostat blocks the flow of coolant until the engine reaches a certain temperature (typically 195 to 210 degrees.) This speeds engine warm-up and reduces emissions. Thermostat failures are a common cause of overheating. Replacement thermostats must be the same temperature rating as the original. This is extremely important on late-model, computer-controlled engines that use the temperature reading from the coolant sensor to regulate the fuel mixture, ignition and other emission functions. Some vehicles have thermostats with a “jiggle pin” vent that allows trapped air to escape from the engine when the cooling system is refilled with coolant.

The water pump is a belt-driven pump that circulates coolant between the engine and radiator. The pump consists of an impeller mounted on a shaft inside a cast or stamped steel housing. Failure of the pump shaft seal or bearing can cause noise and coolant leaks. A defective water pump can be replaced with a new or remanufactured replacement pump.

The radiator is a large heat exchanger mounted in front of the engine. Airflow through the radiator provides cooling for the coolant that circulated through it. Most newer radiators are a “crossflow” design where the coolant flows from one end to the other. Older vehicles usually have “downflow” radiators where the coolant flows from the top to the bottom. Most newer radiators are aluminum, while many older radiators are copper/brass. Most radiators also contain a loop of pipe in the bottom tank or end tank for cooling automatic transmission fluid. A replacement radiator should have the same hose configuration (location and size) as the original and provide equivalent (or better) cooling. For towing applications and high-performance engines, a larger, thicker and/or more efficient radiator can be installed to improve cooling.

The radiator cap is a spring-loaded pressurized cap on the radiator that prevents coolant loss and increases the temperature at which the coolant boils. Pressure ratings vary from five to 15 psi. Caps should be replaced if they cannot hold their rated pressure. Replacement caps must have the correct pressure rating for the application to prevent overheating.

There are two basic types of cooling fan: belt-driven and electric (though a few vehicles have hydraulic fans that are driven by power steering fluid.) The fan increases airflow through the radiator for improved low-speed cooling. Belt-driven fans are mounted on the water pump pulley and may have a viscous clutch that allows the fan to slip at higher speeds when extra cooling isn’t needed. Electric fans may be mounted in front or behind the radiator and are powered through a relay. Some vehicles have a temperature switch to turn the fan on and off, while others use commands from the engine computer and coolant sensor to control the fan. Some vehicles have two electric fans, one of which may be used for the A/C condenser. A fan or fan clutch failure may cause the engine to overheat at low speed.

An engine-mounted coolant sensor monitors the temperature of the coolant. The sensor’s resistance changes as the temperature goes up. The sensor’s output voltage may be used to operate a temperature gauge or warning light, the cooling fan and various emission functions. It is also used by the engine computer to determine when the engine can go into “closed loop” operation (when the computer uses input from the oxygen sensor to regulate the fuel mixture.) A defective sensor can prevent the engine from going into closed loop, cause poor fuel economy and cause higher emissions.

The radiator and heater hoses are flexible rubber hoses that carry coolant between the engine, radiator and heater core. Most applications have an upper radiator hose, a lower radiator hose and at least two heater hoses. There may be an additional bypass hose or other connecting hoses. Some newer vehicles have “branched hoses” where one hose connects directly to another. Most original equipment hose is “molded” to shape, while some aftermarket replacement hose is “flex” hose that bends and can be used in a wider variety of applications. Hoses deteriorate with age and may leak, allowing loss of coolant and allowing engine overheating. Replacement hoses must be the same diameter and length as the original. Always recommend new clamps.

There are two basic types of belts: V-belts and flat (serpentine) belts. Belts are used to drive the water pump and other engine accessories. Belts deteriorate with age, and should be replaced if frayed, cracked, glazed or oil-soaked. Replacement belt length and width must be the same as the original. On vehicles with serpentine belts, the automatic tensioner may also need to be replaced if it is sticking, making noise or cannot maintain proper belt tension. Belt idler pulleys should also be replaced if noisy, worn or sticking.

Clearing Up The Cooling System Confusion -By Larry Carley, Technical Editor
Would you believe cooling system failures are the No. 1 cause of mechanical breakdowns on the highway? That’s what statistics published by the U.S. Department of Transportation tell us. It’s not surprising considering how badly most cooling systems are neglected these days. In April, the Car Care Council offered motorists free vehicle inspections at more than 400 check lanes around the country. The inspections were done to raise public awareness of the council’s “Be Car Care Aware” campaign during National Car Care Month. With respect to cooling systems, here’s what they found: a.20% (one out of five!) of the vehicles inspected had old coolant that needed to be flushed and changed. b.16% (one out of six) had a low coolant level in the coolant reservoir, and 11% had a low coolant level in the radiator. c. 8% had visible coolant leaks. The opportunity for cooling system maintenance and repairs are obviously there. But many motorists never check anything under the hood until a problem occurs. Then it’s often too late and the damage has already been done. An undetected coolant leak or low coolant level can lead to overheating. This can be very damaging, especially in engines with overhead cams and aluminum cylinder heads, because excessive heat causes the cylinder head to swell and distort. This may cause the camshaft to bend, jam or break, or it may crush the head gasket and cause the head gasket to fail. Excessive head also can cause stress cracks to form in the head, which may leak coolant into the combustion chambers. Overheating also can cause pistons to scuff, valves to gall and stick, and bearings to seize. At the very least, a single episode of overheating may damage the thermostat and/or coolant sensor, leading to further trouble down the road if these items are not inspected or replaced after the initial cause of the overheating has been diagnosed and repaired. Simply refilling the cooling system and sending the customer on their merry way is not an acceptable repair for overheating. You must determine why the engine overheated and repair the cause. Treating the symptom (loss of coolant) by adding more coolant may not prevent the engine from overheating again.

Maintaining Today’s Cooling Systems
There’s a lot of confusion among motorists as to how often coolant should be changed. When the Car Care Council asked motorists how often they thought their cooling system should be flushed, here’s the response they received: a.57.2% of motorists said they thought the cooling system needed to be flushed every year. b.15.5% said a flush was only needed every four years. c.13.5% said a flush was needed every six months. d.13.5% said a flush was only necessary when recommended by a service professional. Many of these people have probably never read their vehicle owner’s manuals and don’t have a clue as to how often maintenance is actually needed. These answers would suggest that many motorists over-maintain or under-maintain their cooling systems. The survey didn’t ask them what they actually did, but from what we’ve seen, most probably neglect their cooling systems altogether. The correct answer as to how often coolant needs to be changed depends on the type of coolant in the vehicle and how much time or mileage has passed since the coolant was last changed. Many motorists are under the mistaken impression that today’s extended-life coolants are lifetime coolants and never need to be changed. They are not lifetime coolants. The recommended replacement interval for most extended-life coolants is every five years or 150,000 miles, whichever comes first (not last). Extended-life antifreeze has been in use for about a decade, and GM has been using Dex-Cool extended-life coolant in all of its cars and light trucks since 1996. With older “conventional” antifreeze products, the recommended replacement interval is usually every two years or 30,000 miles. The same recommendation applies to extended-life coolants that have been contaminated with ordinary coolant. If somebody uses ordinary coolant to top off a system that is filled with extended-life coolant, the additive packages can interact and reduce the service life to that of regular coolant. The trouble is, you can’t always tell if extended-life coolant has been contaminated with regular coolant. Most long-life products are dyed orange while most ordinary coolant is dyed green or yellow. But color shifts can occur naturally as a coolant ages, and it takes a lot of cross-contamination to produce a noticeable color shift with some products. As for annual coolant flushes, they’re not necessary – unless the cooling system contains ordinary antifreeze and the vehicle is driven more than 30,000 miles a year. And changing the coolant every six months would definitely be over-maintaining the vehicle and not necessary. The only way to know how often the coolant really needs to be changed is to (1) know what kind of product is in the vehicle’s cooling system (which is often difficult if not impossible to tell), and (2) to check the time/mileage since the last coolant change. One of the best ways to check the condition of the coolant is to use chemical test strips. The test strips change color to reveal both the condition and strength (freezing protection) of the coolant. The test strips react to the level of alkalinity or acidity in the coolant to give a “good” or “bad” reading. If the anti-corrosion additives are depleted, the coolant is overdue for a change regardless of time or mileage. Just make sure you use the correct type of test strip for the coolant being tested (regular or extended life). And if you’re not sure what’s in the cooling system, use a test strip designed for regular coolant. A visual inspection of the coolant is also a good idea to check for sediment or other signs of contamination. Droplets of oil in the coolant might be the result of a leaky ATF cooler or a leaky head gasket. The presence of sediment or rust would tell you the coolant is not doing its job of protecting the cooling system, and is long overdue for replacement. If the system contains Dex-Cool and the coolant is full of red muck (which GM says can occur if the cooling system has not been filled properly and there is air in the system), your customer has a serious problem that will likely require flushing and cleaning the entire cooling system, and possibly replacing the radiator if the muck cannot be removed. The most troublesome applications have been Chevy/GMC S-10 pickups and Blazer/Jimmy models with the cast iron 4.3L V6 engine. These trucks do not have a pressurized coolant reservoir and seem to be prone to air contamination of the coolant.

Enough Freezing Protection?
Checking the strength of the coolant is important to make sure the coolant contains a high enough concentration of antifreeze to prevent freezing during cold weather, and boilover during hot weather. You can use a hydrometer or a refractometer for this purpose, but a refractometer usually provides the most accurate results. If the concentration is low, drain some coolant from the radiator and replace with a compatible antifreeze to increase the freezing protection. A 50/50 mixture of ethylene glycol antifreeze and water will keep the cooling system from freezing up all the way down to -34° F. Increasing the mix to a maximum of 70% antifreeze will keep the coolant liquid down to -84° F! Never use straight undiluted antifreeze or straight water! Straight antifreeze does not have the heat carrying capacity of water, and may cause the engine to overheat. Straight water provides no freezing protection, no boilover protection and no corrosion protection. When adding water to a cooling system, use distilled water. Do not use “softened” water because it contains dissolved salt, which can be corrosive, or hard tap water because it contains dissolved minerals that can form lime deposits.

Universal Coolants?
There are a lot of different coolants in use today. You’ll see orange coolants, green coolants, blue coolants, red coolants, yellow coolants, even pink ones depending on the year, make and model of the vehicle. The proliferation of different coolant types at the OEM level has created a great deal of “chemical confusion” with motorists and technicians about what type of antifreeze should be used to top off or refill late-model cooling systems. When topping off a cooling system reservoir or replacing the coolant in a newer vehicle, therefore, the safest advice is use an antifreeze that meets the vehicle manufacturer’s specifications to maintain the OEM warranty requirements. Once the vehicle is out of warranty, however, you can refill the cooling system with virtually any brand or type of coolant so long as it provides adequate corrosion, freezing and boiling protection. There are essentially three basic types of coolants: a.Traditional North American “green” antifreeze, the original “universal” formula that everybody used until the introduction of extended-life coolants 10 years ago. The fast-acting silicate and phosphate corrosion inhibitors provide quick protection for bare iron and aluminum surfaces, and have a proven track-record of providing trouble-free service in virtually any vehicle application (domestic, Asian or European). But the short-lived nature of the corrosion inhibitors means this type of coolant should be changed every two to three years or 30,000 miles (though some products now claim a service interval of up to 50,000 miles with improved chemistry). b.OAT-based extended-life coolants. OAT stands for Organic Acid Technology, and includes such ingredients as sebacate, 2-ethylhexanoic acid (2-EHA) and other organic acids, but no silicates or phosphates (except in the case of Toyota’s pink extended-life coolant, which adds a dose of phosphate to its extended-life OAT-based antifreeze). OAT-based coolants are usually (but not always) dyed a different color to distinguish them from regular North American green antifreeze. GM’s OAT-based Dex-Cool is orange. Volkswagen/Audi uses a similar product that is dyed pink. But Honda has an extended-life OAT coolant that is dyed dark green and does not contain 2-EHA. The corrosion inhibitors in OAT coolants are slower acting but much longer-lived than those in traditional North American green coolants. Consequently, OAT coolants typically have a recommended service life of five years or 150,000 miles. OAT corrosion inhibitors provide excellent long-term protection for aluminum and cast iron, but may not be the best choice for older cooling systems that have copper/brass radiators and heater cores. It depends on the formula. One ACDelco spokesman said they do not recommend Dex-Cool for older vehicles with all-iron engines and copper/brass radiators. c.Hybrid OAT coolants, also known as “G-05.” This formulation also uses organic acids, but not 2-EHA (different organic acids are used). Hybrid OAT coolants add some silicate to provide quick-acting protection for aluminum surfaces. Silicate also helps repair surface erosion caused by cavitation in the water pump. Hybrid OAT coolants are currently used by many European vehicle manufacturers as well as Ford and Chrysler. One thing the aftermarket has always been good at is consolidation, and today’s coolants leave plenty of room for that. In the past couple of years, many antifreeze suppliers have introduced “universal” or “global” one-size-fits-all coolants that are claimed to be compatible with any new vehicle cooling system as well as older vehicles. The basic idea behind universal coolants is to eliminate all the confusion about colors and chemistry and have one basic product that works in any vehicle regardless of year, make or model. What could be simpler? Not all antifreeze suppliers buy into this marketing philosophy, so you’ll still see the three basic types of coolant being marketed: traditional green for older vehicles and budget-conscious motorists who want the least expensive product on the shelf, an extended-life product that is compatible with Dex-Cool and other OAT-based coolants, and a hybrid OAT for late-model Ford, Chrysler and European vehicles that specify G-05 coolant. But for those who offer a universal “all makes and all models” kind of product, the advantages are obvious: one product that provides full coverage for all applications. Makers of universal coolants say their products are formulated to be compatible with all cooling systems (import or domestic) and all coolant types (traditional green, OAT and OAT-hybrid with silicate). The new universal coolants use unique OAT-based corrosion packages with proprietary organic acids (such as carboxylate) to provide broad spectrum protection. When a universal coolant is used to top off a cooling system that already contains an extended-life OAT or hybrid coolant, the service life is unaffected. It remains five years or 150,000 miles. If a universal coolant is added to an older vehicle that has traditional green antifreeze in the cooling system, the service intervals is also the same as before: two to three years or 30,000 to 50,000 miles depending on what was in the system.

Flush & Fill
When switching to a universal coolant, the cooling system should be flushed to remove all traces of the old coolant when the coolant is changed. Flushing the system removes contaminants and maximizes the service life of the new coolant. Just draining and refilling the radiator is not a complete coolant change because up to a third of the old coolant can remain in the block. If the old coolant is ordinary green coolant, the new universal coolant will be diluted and won’t be able to extend protection much beyond that of the original coolant. The best way to assure a thorough job is to use service equipment that does a complete coolant exchange. Coolant recycling machines take a different approach by filtering and replenishing the old coolant that is already in the vehicle. Corrosion protection is restored by adding new chemicals to the coolant. Universal additive packages are also available for use with recycling machines, or conventional or OAT-based additive packages for domestic or Asian/European applications. The bottom line is this: most motorists don’t really understand today’s coolants or how much maintenance their vehicles require. Consequently, they don’t do anything other than put gas in the tank. So there’s an opportunity there to educate your customers as well as help them avoid expensive breakdowns and keep their cool.

Bill Created to Make Antifreeze Taste Bitter
Washington, DC – A pack of dogs joined with industry and consumer groups in late-July to urge Congress to pass legislation that would require the antifreeze manufacturers to make their otherwise sweet-tasting product less appealing to animals and children. As several dogs looked on, representatives of industry and animal rights groups told the Senate Commerce subcommittee on consumer affairs they want legislation requiring coolant manufacturers to put a bittering agent into antifreeze, which is a toxic substance. Their result – the Antifreeze Bittering Act – has been introduced in Congress, requiring engine coolant that is 10% ethylene glycol to also contain denatonium benzoate, an extremely bitter chemical. Denatonium benzoate, one of the bitterest substances known, is already used in other household products to discourage children from ingesting them. Representatives of the Doris Day Animal League told the panel that 1,400 children ingest antifreeze each year, and that as many as 10,000 dogs and cats a year are poisoned by it. Often, it is the poison of choice for disgruntled people seeking to quiet a neighborhood dog. Subcommittee Chairman George Allen, who invited pet owners to bring their dogs to the hearing, said his panel would act on legislation soon, and that he expected to the full Senate to pass the measure. A representative from one coolant manufacturer said domestic antifreeze producers also support the legislation. He said the coolant industry, faced with a multitude of state and local laws requiring a bitter tasting product, joined forces last year with the Doris Day Animal League to back a national standard. Coolant manufacturers said adding denatonium benzoate would add less than 3 cents to the $4 to $6 it costs to make a gallon of coolant. According to the American International Automobile Dealers Association, the bill would apply only to aftermarket antifreeze sold in retail stores. It would not affect coolants in new vehicles or the drums of replacement fluids used by garages. The House Subcommittee on Environment and Hazardous Material is reviewing the bill.

Source: Reuters

Cooling System Maintenance


  1. Radiator Pressure Cap: In addition to keeping air out of the system, the cap actually does more for anti-boil than a 50/50 mix of antifreeze. Every 1 lb. of pressure raises the boiling point of the coolant by 3 degrees.
  2. Coolant Recovery Tank: An empty reservoir allows more air to be drawn into the cooling system. Air in the system is not a coolant and takes up space that could otherwise be used for coolant. More air obviously means more oxygen in the system. Oxygen allows rust, oxidation and cavitation erosion to thrive in the system. Aeration can speed up corrosion rates in cooling systems by 30x’s. It may also cause coolant foaming and overheating.
  3. Keeping the System Clean: A clean system is vital to the overall efficiency of the cooling system. A 1/16th inch layer of rust is capable of cutting an engine’s ability to dissipate heat by as much as 40%. Many additives specifically state that they are designed to work on clean systems only. Keeping the system clean will go a long way to reducing many cooling system failures. Also a 1/16th inch of rust can raise water temperatures from 200ºF to as high as 700ºF.
  4. Coolant Sensor: Often these are referred to as the Master Sensor because of the many functions they regulate. Corrosion on the sensor or low level electrical charges in the coolant itself can send improper readings to the computer, causing a variety of problems.
  5. Automatic Transmissions: 90% of automatic transmission failures can be attributed to overheating and varnish build-up. The cooler the engine, the longer the ATF life. For every 20ºF increase in ATF temperature, the oil oxidation rate doubles, causing the transmission to potentially wear out twice as fast.
  6. Hoses & Seals: A neglected cooling system will drastically reduce the life of these components. In addition to the damage caused by rust and scale, many of today’s problems are caused by electrochemical corrosion, attacking the inside of the hoses and the surface of the seals.

The Proper Maintenance of this System is Money in the Bank! Engine cooling system short course on protection & maintenance

  • Environmental issues have required engines to run hotter in order to reduce exhaust emissions. Today’s engines run on the borderline of overheating.
  • We have found that many people neglect their cooling systems until it becomes a costly problem. A properly maintained cooling system will provide excellent service for many years. There is more to maintenance than just changing the antifreeze every two years. Little things like replacing hoses and keeping the air flow clean and unobstructed are also very important. The cooling system is just that; a system. We are not just talking about a radiator; but a water pump, hoses, fan, heater, thermostat, engine block, and head(s). The antifreeze we put in our cooling system contains a minimal amount of protection against rust, scale, and forms of corrosion.
  • Cooling system efficiency requires cleanliness. Antifreeze has no cleaning effect. People use tap water (which usually contains minerals) to add to antifreeze. These minerals can quickly overcome the additive package in antifreeze. The additive package in antifreeze is consumed whether you drive or not. The protection from freezing and additional boil-over protection remains the same even when the additives are used up.
  • A simple check for freeze or boil-over protection will tell you nothing about the rust, scale, corrosion, lubrication factor, electrolysis, cavitation, erosion, and pitting that is going on in your system.

Cooling System Facts

  • A national survey found 7 out of 10 vehicles contain rust and scale
  • Over 60% of water pump failure can be attributed to seal failure.
  • Over 50% of engine failures can be attributed to cooling system failure.
  • Just 1/16th of an inch of deposits on 1 inch of cast iron is equivalent to 3-1/2 inches of cast iron, reducing heat dissipation by 40%.
  • If you are overdue for cooling system maintenance, the deposits have begun to build up. If you had a radiator rotted out because of deposits, the engine block and head(s) are in the same condition. Hot spots in the block and head(s) cause engine detonation (ping) and can shorten lubricant life. DO YOU THINK A 30-MINUTE FAST FLUSH WILL REMOVE WHAT IT TOOK YEARS AND TENS OF THOUSAND OF MILES TO BUILD UP? NO WAY! PLUS, MOST FAST FLUSHES CONTAIN ACIDS, WHICH DO CAUSE DAMAGE TO COPPER, ALUMINUM, BRASS, AND ZINC ALLOYS.
  • REFER TO THE RMI-25 INFORMATION PAGE FOR A SIMPLE SOLUTION TO MAINTAIN-ING A CLEAN SYSTEM. Water transfers heat better than antifreeze/coolant. The word coolant is used as a sales tool to sell more antifreeze in the summer. Antifreeze does increase the boiling temperature only slightly. It is better to use 40% antifreeze and 60% mineral free water, this will give you better heat transfer.
  • Exceeding 60% antifreeze in the cooling system can cause overheating.