BJSZED Posted July 5, 2017 Share Posted July 5, 2017 Wondering if anyone else on the forum has converted to Evans Waterless Coolant ? I just made the switch and am considering going to a 7 psi rad cap to reduce strain on the hoses etc. If anyone else converted, what cap are you running and thermostat temperature? Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 5, 2017 Share Posted July 5, 2017 Wondering if anyone else on the forum has converted to Evans Waterless Coolant ? I just made the switch and am considering going to a 7 psi rad cap to reduce strain on the hoses etc. If anyone else converted, what cap are you running and thermostat temperature? I've been running their straight NPG (was NPG-R before they discontinued it). I'm running the 7psi cap and a 185 deg thermostat. I did also convert to the diesel water pump, just to get some extra flow - the straight NPG has a bit lower thermal capacity but the much higher boiling point made it worth the effort. It's been working great for me for some time now. Quote Link to comment Share on other sites More sharing options...
BJSZED Posted July 5, 2017 Author Share Posted July 5, 2017 Thanks Tim for your response, I'm going to call them today with a couple questions. If I may ask, how did you handle coolant recovery? I have a recovery bottle in place and the coolant expands into it and returns to the cooling system after cool down as designed. Now, seeing that the Evans coolant is hygroscopic ( will absorb water even fro the air ) my concern is that it will absorb water from the air in the recovery tank ? Water is really the only thing that can screw up the properties of this coolant. Quote Link to comment Share on other sites More sharing options...
BJSZED Posted July 5, 2017 Author Share Posted July 5, 2017 Well, I called and will post Evans response to my questions for anyone considering this product. My concern was absorbing moisture from air in the recovery bottle. This will happen according to Evans but it will take time to build up water in the system. The preferred method is to run the cooling system old school like my 240z originally was. You can have an "overflow bottle '' but don't want any fluid in it so it's not recycled over and over. He said to lower the coolant in the rad an inch or so or let it puke out what it doesn't want from expansion. And I can keep the overflow bottle but wouldn't have coolant in it, just there to catch any excess in case it gets real hot. The idea here is that the system will build approx. 6 psi hydraulic pressure which will only compress the air in the rad but that wont be enough to overcome the 13 lb rad cap which will keep the system sealed preventing any moisture from the atmosphere from entering. So, new school coolant with old school air space in the rad.....too easy ! Quote Link to comment Share on other sites More sharing options...
BJSZED Posted July 8, 2017 Author Share Posted July 8, 2017 Well, That was a good theory but failed in practice. It worked fine while running, no coolant expanded to the reservoir tank but when cooling down after the engine stopped, the vacuum valve built into the bottom of the rad cap opens allowing air back in. Maybe, I'm overthinking this and need to just occasionally check water content ? Three percent is the maximum allowed. Quote Link to comment Share on other sites More sharing options...
sugisan Posted July 13, 2017 Share Posted July 13, 2017 How did you know the vacuum valved opened to let the air back in? Quote Link to comment Share on other sites More sharing options...
BJSZED Posted July 15, 2017 Author Share Posted July 15, 2017 (edited) I left a little coolant in the overflow bottle and it sucked it from the reservoir. The only way back in is through the vacuum valve. I have spoken to Evans again. They still recommend keeping an air space in the rad. I might install an expansion tank with a rad cap on it and put a zero pressure cap on the rad, that way the rad can be totally full and the expansion tank would act as my air space. The vacuum valve in the cap would still open though. Edited July 15, 2017 by BJSZED Quote Link to comment Share on other sites More sharing options...
BJSZED Posted July 15, 2017 Author Share Posted July 15, 2017 Respose from Evans on my testing: Hi Brent-Thank you for your thoughtful inquiry. I reviewed your questions with my manager, Evans' Technical Director Dave Wright.The air-over-liquid condition in the radiator and in the overflow, allows a siphoning situation which could pull more moist air back and forth. Coolant at operating temp will "give off" some moisture, and the cooling "pullback" will suck some back in. Over a very long time, in a humid climate, some moisture could accumulate in the system. Like 3% in 10 years-maybe, in Dave's explanation.Our suggestion: Maintain the air space in the rad, and leave the overflow tank empty. It is expected that due to the inherent minimal expansion, and minimal pressure differential, the coolant will never release out of the rad. The secondary cap seal, or "vacuum breaker" may just momentarily "pop" to equalize pressure as needed, then snap shut. No coolant involved, very little air, and very little moisture will transfer.If you'd like you can send us a small sample of coolant from; A) the engine/ radiator, and the expansion bottle when cold, we can verify actual water content as a baseline.Evans also now has a lower-cost refractometer available, p.n. E2196 @$29.95 to allow you to monitor the system going forward.Please contact me with any further questions.-Pete Quote Link to comment Share on other sites More sharing options...
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