Coolant questions - NPG and others

Anyone here, besides ncmountainman run Evans' NPG coolant? I noticed that their website shows three different versions: NPG, NPG+, and NPG-R. I couldn't find anything on their site about the NPG-R stuff though.

nc, any concerns about corrorison damage? Their site talks about sealing off the system, because it'll absorb moisture from the atmosphere. What happens if the system pulls fluid from the overflow back into the radiator? Isn't the overflow vented, to allow room for the boilover to flow back there? With no corrision additives, I'd think it'd be a concern, but if I knew, I wouldn't be here, asking questions. :)

I've had one boil over on my wr450 - it was 90 outside, and it was slow, technical stuff. Right now, its 95 outside, and its supposed to be close to that all week. :) So, that prompted me to do some coolant research. I'm skeptical of stuff that you add to your oil to keep the bike cooler - I'd rather leave that job to the radiator, and let oil do what oil does - lube the engine.

What about stuff like engine-ice, and water-wetter? Any experience with those products?

Also, does anyone have those carbon-fiber air-intake-shroud-thingies installed?

Do those make a difference?

Thanks for the info!


NPG-R and the overflow bottle to allow for expansion. I have not seen any issues yet. I think the overflow bottle is sealed tight with the cap. :)

OK, NC MM calls me a sissy because I run pink coolant! :D I use Toyotas (hey, get a killer deal on it) SLLC also know as "super long life coolant". It contains no silicates or borates, its premixed and they do not want you to use tap water or add any water for that matter. So I suspect its distilled etc. Its designed for aluminum engines, and engineered to go 90K on a factory fill, 60K there after. Of ocurse, I change it every year on my bikes. and if it's good enough for those Yamaha heads on Toyotas, it has to be good enough for Yamaha heads on Yamahas! :) It comes in a 1 gallon container just like any other coolant, but it will have a gold cap on it. Toyota also sells LLC (long life coolant) which has a red cap and is not premixed. I would only use the SLLC, so make sure you freindly Toyota parts guy sells you the correct stuff with the gold cap. It will also mention on the front its 50/50 too. :)

NPG-R and the overflow bottle to allow for expansion. I have not seen any issues yet. I think the overflow bottle is sealed tight with the cap. :)


Whats the difference between NPG-R and NPG? I see you can buy all three (NPG+, NPG, NPG-R) from their website, but they say nothing about NPG-R.

How long have you been running it, and did you switch to it because you were boiling over?


The "R" in NPG-R stands for racing version with reduced viscosity for higher flow rates and less cavitation! :)

General Info:

EVANS lifetime, corrosion free, WATERLESS engine coolants have been proven on professional race circuits and private multi million dollar test tracks, exotic engine dynomometers, and in competition with virtually every major sanctioned body of racing including FORMULA 1, NASCAR, NHRA, SCCA, IMSA, IRL, Grand American, NMCA, ARCA, AMA, WERA, American Lemans, SCORE Off Road, World Rally up, and numerous Boat Racing Venues.

Run Faster - Run Better - Never Overheat!

NPG-R is specifically formulated to handle the extreme conditions of racing and high performance automotive, marine and motorcycle applications. The reduced viscosity of NPG-R makes it more compatible with small tube copper-brass radiators while providing the superior cooling of Evans Waterless Coolants. Although NPG-R is safe for all metals and contains no water, an annual coolant change is suggested for racing vehicles. For maximum corrosion protection, high performance street driven vehicles running NPG-R should change coolant every other year

Evans NPG Coolant will transfer 27.5% more heat energy than water in your race engine, due to NPG's molar heat of vaporization and high saturation temperature.


Increases Power

Extends cooling performance

Improves durability

Provides low, or no-pressure system

Protects from boil-over

Permits increased compression without detonation

Permits more spark without detonation

Eliminates system scaling and reduces corrosion

Permits use of a smaller radiator

Permits smaller frontal openings to improve aerodynamics

Eliminates pump cavitation

Prolongs hose life

I'm running Engine Ice right now and have had no issues thus far. However, I'd like to give the NPG a try when it comes time to change it out. How important is it to flush the system with their prep fluid? Can I just do a regular water flush and go from there? Gracias...SC

I ride out here on the edge of the mojave desert in the piute mountain area. we ride some of the nastiest single track there is. every coolant has puked out everywhere. i'm running npg+ now and have zero over heating problems. the only problem now is knowing when to stop,before when coolant started steaming i knew to stop & let the bike recvr/cool down. make sure you also get the prep fluid for small engines as recommended by evans,a gallon is enough for two bikes,so you can sell it to a riding buddy to offset the cost. it's kind of expensive,but,well worth it. :)

minion,i would reccomend the npg-r as indy stated its thinner for better flow,the r also has a higher boiling point (400 as compared to 375) the overflow tank is not needed,the npg-r does expand a little more than 50/50 but it finds a happy spot about a 1/2" below full and just stays there. the tank is just unnescesary weight :) there is no corrosion from water as there is none,and they say its superior for lubricating the pump. hey toyotie that pink stuff will still boil out at 250-275 :D and if i'm in a situation where that happens, its better to have coolant circulating in a hot motor than to have it circulating to the ground :)

...hey toyotie that pink stuff will still boil out at 250-275 :D and if i'm in a situation where that happens, its better to have coolant circulating in a hot motor than to have it circulating to the ground :)

I have never had it boil out. I can see my overflow level rising indicating things getting a little warmer. But never more than a few inches. NC, your too slow of a rider, not getting enough air flow across those radiators. :D:) Just funning with ya, I know your a hot dogger in the trails. :D

So you have to buy that prep crap too? Are you sure?

You can flush it with rubbing alcohol and it will eliminate any water! You need to flush the system with a non water based fluid. I used cheap 99% Isopropyl Alcohol for $3.50 cost. :)

How do you get all of the rubbing alcohol out after you flush it?

Drain it out at the pump and then just leave it open to the air and any remaining drops will evaporate quickly! :)

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