#EngineCoolant

TTAC Commentator ErikStrawn writes:

Over the years I’ve tinkered with a bunch of different cars. Back in the day, you could put green ethylene glycol coolant in every car and it worked fine. If you had a car with the brand new DexCool, it was recommended to drain it and refill with the green stuff. Then some manufacturers went to the red stuff, and VW/Audi went to some other stuff that sludges up if mixed with the green stuff.

A couple years ago I bought an insurance auction VW Beetle TDI, and when I replaced the front end/radiator/etc., I flushed the engine out with water and switched the car to traditional green coolant.

My ’06 Mustang has 140K on it, and living in a constant state of having too many projects, I’ve neglected to change it until now. I’m of a mind to flush it out and run green coolant, but I know aluminum motors aren’t exactly tolerant of the green stuff.

I intend to transition my entire fleet to one coolant. What is a good one-size-fits-all coolant that is readily available? I’m in Oklahoma, and it freezes here, so running straight water is not an answer. Should I stick with the green stuff and replace it more religiously?

The Mustang is bone stock and ultra-reliable, so I don’t want to run coolant that has a propensity to turn acidic and erode the cooling passages. Is the red stuff any better? What is it called and can I find it at a truck stop at 3 a.m.? Does VW’s coolant have any advantage?

Longtime TTAC Commentator ajla writes:

Hi Sajeev,

I do a more through job at the time of purchase, but every year after I do a drain/refill on the radiator and replace some transmission fluid by using my fluid extractor to vacuum up as much ATF as possible through the dipstick tube.

I know that I’m not getting all the fluids exchanged this way, but my question is how much of a positive impact is this regiment actually having on my cars? Am I just wasting my time? I haven’t suffered a mechanical failure since I started doing this, but I don’t know if that proves much.

Keep in mind that the vehicles I tend to own are 20 to 30 years old.