I have been hearing increasing complaints from mechanics and dealers regarding problems with Dexcool antifreeze. According to what I am hearing GM is telling dealers to quietly change back vehicles equipped with Dexcool when they exibit a muddy, gritty residue in the recovery bottle. Supposedly GM is trying to keep quiet about the problem and it is not just an isolated problem with a few vehicles. Anybody have the real story.

 

As a mechanic, I can tell you basically the same. Dexcool and standard ethylene glycol antifreeze work on two seperate principles. One keeps particles suspended, the other creates a nice, thick sludge. Mixed, you get little chunks that rise to the top and clog everything in their path. The biggest problem with dexcool though, is the same as platinum plugs. The mindset of the "maintenance free" 100,000 miles. If you treat dexcool like any other coolant, and flush it at 65-70k, You will more than likely not see as many problems. I would definitely not recommend trying to convert a car that runs the green over to the orange though. When I was a parts guy, I had numerous cutomers, both DIYers and techs, preach about conversions and horror stories. I personally have seen both kinds of coolant in horrible states. The best advice to give someone is if you can, flush it below recommended intervals(most service manuals, even on 100k M.F. cars have a "severe service interval, usually sooner than the advertised mileage. If you read the fine print, 85% of american commuters fall under the severe service catagory) and if you can, use distilled water for top offs.
Mike

 

I've had good luck with the dexcool myself. I switch mine over sometime around 5 years ago. No problems at all. I really, really flushed the block and radiator good though. I didn't switch for the extended change intervals--did it for the better heat transfer properties.