evans coolant

[chris kuba]

I recentlly read a thread about the Evans coolant. I went and got a gallon for my '99 KDX 200. I bought the bike used and don't have a manual. Could anyone give me some advise on how to properly flush the existing coolant and how to replace with the Evans properly. I also need to know how much it takes or will I know when it's full just by looking.

 

[Zerotact]

If it were me, I'd use the drain plug by the water pump housing, I have heard of people flushing the cooling system with some non toxic antifreeze. I think the name of it is sierra. I have also heard of things as crazy as sucking the rest out with a shop vac on the radiator cap...

Basically you want to get all of the old style antifreeze out.
you might be able to find more info on evans cooling's website.
http://www.evanscooling.com/

 

[JasonWho]

---

 

[chris kuba]

I think I got it all out. I even pulled the rads off to make sure and to fix some of the cooling fins that were bent. I was also wondering what u guys did with your overflow bottle. I read that some guys were removing them. I pulled mine off and just put the long hose onto the outlet by the cap. Is there anything special I need to do with that? I ask this because it seems to me that if the bike accidentally tips on it's side most of the coolant could just run out. Or should I just keep the bottle on there, weighs just about nothing anyway.

 

[holmy]

Coolant won't run out the overflow hose when tipped over. A lot of guys run the hose so it drains on the exhaust if it overheats, you can smell it before you lose too much

 

[JasonWho]

---

 

[Robcolo]

Here's the "skinny" on Evans coolant. Water -distilled or other boils at a little over 200deg. Mix it with antifreeze [ethylene of propylene glycol] and the boiling point of the mix goes up just a little -maybe to 235 or 245F. The evans coolant [actually a mix of anhydrous propylene & etehylene glycols] boils at roughly 365F. Add just a trace of water and your boiling point comes back down to the 235 range. So, to effectively install the Evans coolant you must remove ALL of the water from your system. [No you can't install 100% Prestone or other brand --read their labels --water is the second ingredient] You did the best thing --took it all apart, but there could still be some fluid remaining in the water pum,p. I flushed my cooling system twice, then ran it up to temp with just plain water. When hot, I drained it then hooked up the shop vac to the rad inlet and sucked air through the system [all drain & air vent screws removed] for about 1/2 hr. There's also a good reason to keep the expansion tank on there - - the Evans coolant expands much more than does water when heated and at $35 a gal you don't want to waste any. IMO, the expansion tank located right behind the rad blocks a large amount of air flow - so I relocated mine behind the headlight. Once it's installed, you'll never overheat again ! ! !

 

[JasonWho]

---

 

[canyncarvr]

re:'- the Evans coolant expands much more than does water when heated..'

I thought it expanded much less when heated. That was one of its advantages.

I thought that 'cuz such has been posted before.

So, which is it?
********

Well, I'll tell 'ya. I just got off the phone with tech support at evans. A few facts:

1. They want the water left in the system to be less than 5% of the total volume. So, it is not necessary to remove 100% or every drip.

Still, the more removed is better....and they make a hygroscopic 'prep' product that will do this. Drain your engine, refill with the 'prep' product. Run it for a week. Drain. Refill with NPG+.

2. The NPG product expands 'similarly' to aqueous coolants. The pressure an NPG cooled system generates is much less than an aqueous system because of the elimination of vaporization. They (evans) recommend a 7psi cap. Most engine systems (pre npg) run in the 12-15psi range.

So....run the prep to remove the water. Note: Motorcycle coolant systems are notorious for being hard to drain (completely). Hooking up a shop vac may well work fine, but the prep product will absolutely remove every drop. Not that you have to (read above) but if you have NO water in the system, then you don't have to wonder if what you DO have is 5% or more, 'eh?

BTW..for those of you with diesel bikes...the amount of aqueous coolant you can retain drops to 3% capacity by volume. ;)

Don't bother taking exception to any of the above. It's from evans tech. Call them if you have a question. 610.323.3114

 

[chris kuba]

That whole thing about getting all the old antifreeze out bothers me still. I did fill the rads with the evans after emptying the old out first like it says on the container, then drained that out after warming it up. Then I re-filled with evans and left it at that. I really wonder if even that will get all the old out or should I do it one more time? It cost me $27 for the gallon and I still have 1/2 gallon left.

 

[chris kuba]

Sorry CC I didn't see the second page post there. I will see if I can find the stuff from Evans to do it properly. I will feel much better then.

 

[BRush]

Intriguing stuff. Since evans coolant is 100% propylene glycol, its heat capacity is substantially less than water or coolants containing water. Your engine is going to run hotter with evans. On the other hand it has a boiling point so high that there’s almost no risk you’ll ever see it. So their theory must be that it is better to accept higher operating temps in order to insure that your bike will never boil. This is one of those cases where only time will tell whether that’s a good tradeoff for a KDX engine.

 

[KelvinKDX]

i've been thinking about using the Evans coolant - and now would be the time as i am awaiting the return of my engine from Eric Gorr who is doing a bottom end rebuild on the engine for me.  At least i know for sure that there is no aquious coolant in the system when i start.

I'm going to use it in my wifes KX100 too - it has no coolant resivior tank.  We took the bike out for its' first real ride Sunday and when my wife got stuck in some slick hill climbs where she was getting no air through the rads but high revs - the bike began to really steam (boil over). 

I'm assuming that 1 gallon will be enough to do both bikes.

 

[Robcolo]

Originally posted by BRush
Intriguing stuff. Since evans coolant is 100% propylene glycol, its heat capacity is substantially less than water or coolants containing water. Your engine is going to run hotter with evans.

The original NPG formula was propylene glycol but the NPG+ product is a propylene + ethylene glycol. You're right - the glycol has substantially less heat capacity than a water based coolant BUT, in practice the engine actually runs cooler --and in my case -- much cooler !! BE [before Evans] my engine, pipe and radiators were too hot to touch - practically smoking. Now, I can lay a hand on all of those parts after riding it hard. In theory, water with it's greater heat capacity will remove more heat, but in practice - where the water is boiling and insulating the metal surfaces with steam bubbles, far less heat is actually removed from the engine.

 

[canyncarvr]

re: 'So their theory must be that it is better to accept higher operating temps..'

From their website:

'Engines run more efficiently when they're hot.'

and...

'When you eliminate trapped engine heat in the cooling system, you can run hotter, which increases your engine's efficiency. '

So, yes, that could be posited as their theory...in conjunction with the lack of vaporization and its associated problems.

As is true with many (which is to say, all) things, there is a 'giveth' on one end and a 'taketh away' on the other.

 

[BRush]

I was wondering about the difference with NPG+. Thanks. There are a lot of factors that could come into play to explain why one bike might run hotter or cooler than another, but if you want to reduce it to the effect of just the coolant choice then I suspect that the only time Evans could be said to run cooler than say, Maxima coolant or Engine Ice, would be in a boil over situation with the water based stuff. Physics and thermodynamics being what they are, I can’t see an Evans engine running cooler than a water based coolant - assuming no boil over for the water based system. An engine running at X load and Y ambient conditions is going to produce a given amount of heat. Given the same coolant flow rate in either case, the fluid with the greater heat capacity is going to produce the lower temperatures. All of the above assumes the same fuel, and a unmodified cooling system.

The Redline site has a simple, effective graph illustrating that point. They heat a bar of aluminum to 304 deg F then dunk it into a measured quantity of coolant ( which is at 215 deg F @ 15psi prior to the dunking) then see how long it takes the temp to drop, and where it drops to.

But the no-boil over assumption is a big one. Once boiling starts, things go to you-know-where in a hand basket quickly and the temperatures will spike upwards which is why I think that Evans has possibilities. Since all you guys are doing real-world testing, I’ll give it a season or two and see what the consensus is then ;)

Per the efficiency argument. Maybe they do – for a bit. There is definitely a point of diminishing returns, because engines are also a collection of metal parts that fit and move together at certain clearances. The designers only allow so much margin for thermal expansion at higher than design temperatures before some of those clearances will be adversely affected. Where is that point on a KDX? I don’t know.

 

[chris kuba]

To answer KelvinKDX's question, I think the gallon will be plenty to do both bikes as long as you use the recomended flush and not the gallon of Evans. I filled and drained the KDX twice and still have a half gallon left. I will let everyone know what or if I notice any changes....good or bad. Taking the first ride tomorrow.

 

[Jaybird]

Folks, lets get real here.
Evans is 100% propylene glycol.
You can purchase 100% propylene glycol at any AutoZone for about 5 bucks a gallon.
But then some feel much better throwing 27$ a gallon down the drain.
(sheesh)

 

[JasonWho]

---

 

[Robcolo]

Originally posted by Jaybird
Folks, lets get real here.
Evans is 100% propylene glycol.
You can purchase 100% propylene glycol at any AutoZone for about 5 bucks a gallon.
But then some feel much better throwing 27$ a gallon down the drain.
(sheesh)

Jaybird -- the Evans product [actually it's a mix of ethylene & propylene glycols - the NGP+ that we're using] works by eliminating all but 1-2 % water in your system . Read the second ingredient on that $5 jug of propylene glycol at Auto-Zone. Being a chemist though, I felt the same way and got a gallon of it, then set up a vacuum distillation apparatus. As you distill,you can watch the temperature of the batch and when the rising rate flattens out, almost all of the water has been distilled off. After cooling there was a white residue suspended in the glycol - -probably the water soluble additives. It will eventually settle out or you can filter it. Ethylene & propylene glycols are flammable so use caution if you try this at home. Ethylene glycol is very poisonous so don't breathe hot fumes. Hot Propylene glycol tends to oxidize and decompose if exposed to air, thus the need for vacuum distillation.

 

[JasonWho]

---

 

[Jaybird]

OK, ok....100% "inhibited" propylene glycol.

A chemist will also recognise that no coolant/water mixture will be as efficient as a clean water (prefferably deionized) with an added surfactant will be.

 

[Robcolo]

jaybird - - you have to understand the REASON for using the Evans coolant - - and it has nothing whatsoever to do with the efficiency of the heat transfer medium. First, you have to get the heat INTO the transfer medium. Go to Evanscooling.com and snoop around on their tech pages as have a number of Nascar & top fuel dragster teams.

 

[skipro3]

My personal experiance with Evans NPG+ is that it doesn't expand as much as water. Full, I lose about 3 ounces on a hot day of hard riding. If I don't top it off again, I don't lose anything on successive trips out. I took the overflow tank off to facilitate air flow and hooked up a digital thermometer to the outside of the cylinder. There was no difference in engine operating temperature with or without the overflow tank. This may be because most of my riding is very tight single track where I very seldom get into 3rd gear. Mostly 1st and 2nd gear stuff. My bike has gotten up to 240+ degrees without any problems running NPG+. (But I can sure feel it through my boots!)

And thanks to Robcolo for the lab report! That's some research you've provided us with.

 

[Robcolo]

Skipro has just discovered one of the "secrets" of the KDX universe. Once you quit adding coolant to the reservoir, you never have to add any again. You can fill that little bottle to the very top, and at the end of the day it's almost empty. My guess is that joggling over rocks & bumps shakes the liquid up & into the overflow hose and it simply trickles out as the day goes on - at least down to a certain level. I keep no more that 1/2" in there and haven't needed to add any yet this year.