Frequently Asked Questions

How much RMI-25 do I need?
The good news is that, unlike other radiator treatments, it is impossible to put too much RMI-25 in your radiator. Theoretically, you can run 100% RMI-25 in your radiator and the only difference would be quicker results. RMI recommends eight ounces of RMI-25 for a cooling system with a capacity up to five gallons. For cooling systems above five gallons, we recommend a minimum dosage of two ounces per gallon. When used with distilled water only, and no antifreeze, we recommend doubling these dosages.

Cooling System
4 Gallons 8 oz.
5 Gallons 8 oz.
6 Gallons 12 oz.
8 Gallons 16 oz.

How do I use it?
Pour the recommended dose into the radiator and drive.  Radiator draining and refilling is usually not required.

How often do I use it?
Be sure to retreat your cooling system every 15,000 miles (300 hours).

How quickly does it work?
At recommended dosage, corroded systems are cleaned in two weeks (15 hours) of normal driving.

How do I know it is working?
You will see corrosion floating on the surface.  It can be flushed by overflowing the radiator at the cap or recovery tank.  In extremely rusted systems in which rust penetration has occurred, good cleaning action may reveal a leak. Quality stop-leak is recommended to seal such openings. if leakage persists, see a radiator specialist.

What can I use it with?
RMI-25 is compatable with all types of antifreeze, including high- and low-silicate types of antifreeze.  RMI-25 can be used in all types of radiators, and is safe for all metal, metal finishes, and aluminum engines.  RMI-25 is especially recommended with all types of water wetters.

What are other uses for RMI-25?
RMI-25 can be used in heating systems that use hot water.


Does RMI-25 renew the additives in coolant?

What happens to the deposits that RMI-25 has dissolved?
The rust, mineral, and other deposits become a soft floating harmless material. These deposits are purged from the system into the coolant recovery tank. On large diesels the deposits are trapped in the coolant filter. Where no recovery tank or filter is used, it may be necessary to drain the radiator.

Does RMI-25 change my maintenance schedule on coolant?
Yes! It is like recycling the coolant without removing it from the system.

Will RMI-25 prevent cylinder liner pitting and erosion in diesel engines?

I don’t know how old my anti-freeze is, what should I do?
It is best to change it. Use distilled, or de-mineralized water to mix and add RMI-25.

Is it OK to treat the new coolant with RMI-25?
Yes! Remember, coolant has no cleaning action, and RMI-25 gives you that extra edge.

Can I use RMI-25 with water only?
Yes! Be sure you use mineral free water in your cooling system.

Does RMI-25 reduce the chance of water pump failure?
Yes! Over 60% of water pump failure is caused by seal leakage. Granulated rust and minerals circulate in your cooling system, acting as a lapping compound on your seal and shaft. RMI-25 turns these granules into a soft material.

I have a new vehicle. Is there any advantage to using RMI-25?
Yes! The use of RMI-25 in a new vehicle will provide greater protection against deposit build up, will remove foundry rust and deposits, and promote greater heat transfer.

Does RMI-25 extend cooling system longevity?
Yes! There is nothing you can buy on the market today that does a better job of keeping the cooling system 100% efficient.

Does RMI-25 clean so well it will create leaks in the system?
Sometimes. This may happen if the cooling system has been seriously neglected and is on the edge of failure.

Is RMI-25 a good supplemental coolant additive (SCAs) for my diesel?
Yes! Below is an explanation of what SCA’s are all about.


SCA is required in all diesel engines with wet sleeves (press in cylinder liners). We recommend RMI-25 cooling system treatment for all diesel and gasoline engine cooling systems, whether they have wet sleeve liners or not. SCA should be added to your anti-freeze solution based on diagnostic testing results. Other SCA’s, which contain silicate, borate/nitrite or molybdate/nitrite/phosphate are designed to inhibit cavitation, erosion, corrosion, and scale formation. These additives can be applied in two ways; either bottled liquid or via a coolant filter treated with SCA. Testing for proper SCA content should be done on a regularly scheduled basis and the proper amount of SCA added as needed based on cooling system capacity. Note: “Other” SCA’s do not contain a cleaner, and the rust & oxidation inhibitor will only work effectively in a clean system. The overdose of other SCA’s results in an overcharged system and can cause cooling system problems (green goo or solder bloom). This is the reason a test MUST BE DONE and the proper amount of SCA must be used. RMI-25 does not use silicates, borates, nitrites, or molybdate/nitrite/phosphate chemistry. Therefore it also eliminates the many problems which may occur with products using those chemicals in their formulation. RMI-25 is safe for all metals, plastics, hoses and seals. It is compatible with all types of antifreeze/coolant solutions and metal-based stop leaks.