I want to thank everyone who contributed, and especially thanks to funola, for the generous offer. I finally pulled the engine in the non-turbo car, and the housing on that car was in very good shape, so...even though I'd "fixed" the other, I think I'll just being keeping it around for a spare.

I would like to hear more about people's experience with Evans waterless coolant though. I've read up on it, and it sounds very intriguing just from the idea that it keeps pressure out of the system, it would make sense that with an older car, the absence of pressure would be a nice peace of mind from some obscure hose you never knew was in the car blowing.

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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission.

Let me tell you why I won't run NPG. Glycol, as the -ol suffix suggests, is an alchohol. At room temperature, you can put a match out in it. But the flash point is around 215-220f. At that point, the match trick will yield a burst of flame. The auto-ingniton temperature is around 800f, which means that it doesn't need an ignition source if it gets that hot.

Now you might say, so what, gasoline is flammable and so is Diesel, and I have a whole tank full of that. But the engineers who designed your car knew that fuel is hazardous, and applied proper caution in designing the fuel system. For example, fuel isn't routed through your passenger compartment, nor does it come close to the exhaust manifold. But coolant flows through the heater core which practiclaly sits in your lap. And it flows through the thermostat housing directly below the manifold. And so you need to think carefully about whether a leak could turn into a much bigger problem. I don't know of any car that's actually caught fire because of NPG, but it's not a risk I'd take.

You have a better chance of getting struck by lightning before the Evans coolant catches fire in your cooling system. Conventional EG is also flammable at temperature. It was a problem years ago with gas-powered ambulances. Break a hose, and the ambulance was toast.

If it was such a fire hazard, I doubt it would be used in racing applications, which is where it got started.

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'83 300D, 126K miles.

Hey, glad you found a good one. One question I have is why the housing got so corroded? WHAT ELSE is corroded in the process?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

That's what worries me too! I'm really hoping it's only the aluminum bits. I've seen the horror pictures of cavitation, and hope that's not been going on as well. It is one reason I'm considering the waterless coolant going forward...one of the claimed benefits is no-cavitation, because it doesn't boil, and thereby produce steam...these are the theories. And certainly the corrosion of aluminum is eliminated too. Jay Leno's garage has a you tube video of the stuff, and how he used in in a Duisenberg to stop corrosion that was destroying the aluminum.

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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission.

A 50/50 mix will be very hard to ignite. OTH, in pure form, it's dangerous above the flashpoint, which isn't too far above normal operating temperature.

I doubt that it is used in motorsport, at least above the dirt track level. Glycols are VERY slippery when spilled on an asphalt track...most race sanctioning bodies won't allow it. SCCA, for example, bans glycol coolants for road racing. Same for NASA pro racing. Every serious racer I know uses pure water and Water Wetter.

I think everything Mxfrank says is true. However, I am not concerned with the flammability of Evan's coolant. It would require both a significant heater core leak, plus a flame source to ignite the coolant in the cabin. Many things in the cabin can also burn (carpets, seats, anything plastic, ...). If conscious, I would not stay in the cabin were anything burning.

I also use Duracool refrigerant, which is flammable, and that terrifies many people (due to rumors spread by Auto AC shops?). R-134A is also flammable plus produces poisonous phosgene gas when it burns (Germans used that in WWI). Even freon burns. Despite use in millions of cars, there has been no report of a fire from the use of a HC refrigerant.

Evan's coolant has a very low vapor pressure, so I doubt it would burn violently like gasoline. It must first turn to a vapor to burn. For fun, I might heat some Evan's to boiling (~400 F) on the stove, then light it with a match (outside). I actually did that with some liquid Duracool (mostly propane) I caught in a styrofoam cup when venting some refrigerant. I poured it on the concrete and lit it. I expected it to deflagrate or such, but it burned very mildly, much weaker than an alcohol flame. Indeed, you could barely see the flame. It was bubbling slowly, so not a lot of vapor generated. It was so non-threatening that I let my 11 yr old daughter light some as a science experiment (light this clear "water"), I expect Evan's would be even more subdued.