A warning about Evans Waterless Coolants

I run Evans in my 1984 & 85 M-B diesels and last summer converted my 2002 3.8L T&C minivan to Evans though didn't get many super hot days testing on it. "Hot day" here means >110 F to you Easteners. Best test was the 1984 diesel, climbing the I-5 south grade to L.A. on an August afternoon (~100 F), a stretch I understand where new car designs are proven. It hit 102 C (normally runs 82 C), which is about what we saw with 50/50 mix. I agree w/ traditionalists who say that ethylene glycol/water has been around for decades, but so has the associated corrosion. Evans does have less heat capacity so less cooling capability than pristine 50/50 in a new car, but my hope is that after a few years the lack of corrosion makes the cooling system work better with Evans, plus I hate changing those parts.

One caveat, my 1985 diesel starting running hot last Fall and thru the winter (~95 C vs 82 C) and creeping towards critical 120 C at long stop lights unless I rev'ed the engine. But, this was after 2 years running Evans w/ no problem. Started after I installed a new T-stat and added a tube of Aluma-Seal (preparing it for my son, possible heater core seepage). A month ago, I recovered the Evans and swapped to pure water + anti-rust and the old T-stat. Seemed to still overheat slightly, then stopped after a few days, running at 82 C since. One suspicion is that Aluma-Seal forms a clog in Evans. But, the T-stat could also be the culprit. The M-B T-stat is double-headed. One plug must open and the other close a bypass in the housing. People that remove the T-stat find their engine overheats, which might be how some stories started (most M-B or Euro-cars?). More testing.

Many false stories about Evans spread, many by competitors. Most have little scientific basis. But, Evans is also a bit wrong in claiming that vapor formation in the head lowers heat transfer. Boiling initially greatly increases heat transfer. In the extreme, you get "film boiling", which is a continuous film layer that does decrease heat transfer, so they are partially correct. BTW, if you boil used Evans to drive off the water, do so outdoors. I did that inside on the stove, thinking the faint vapor coming off was water. I later noticed greasy drops on the vent screen, so I had been boiling the Evans. It is supposed to be safe to drink. The original formula used propylene glycol, which is a food additive, but I understand they now mix ethylene glycol, having found that the mixture is non-fatal, but please don't test that.

On the "bad cooling science" list, add the one about needing a flow restrictor to "give time for coolant to sit in radiator and cool". A manufacturer considered that bizarre and traced the source to 1940's cars that would burp fluid out the radiator cap from too much pressure, which a restrictor fixed. Read up: Stewart Components, Tech Tip #3 - Thermostats & Restrictors

I plan to convert my 60's Mopars to Evans, and have several drying out thoroughly, after flushing w/ citric acid.