last weekend I took my car ('96 chevy blazer) to get an oil change. Soon they come get me to show me my radiator… they have the cap off and the opening is stuffed with a mud/clay like substance. They tell me they have seen this when the “red antifreeze” that came in the car from the manufacturer gets contaminated with the “green antifreeze”. This could very well be my fault then.
I had been noticing a fluctuation in my temp guage that seemed abnormal the last week or two so I had them do a chemical flush… then on their own and without charging me extra they did 3 more hot water flushes to get the crap out.
I think I got of lucky… no leaks and the temp guage is rock solid now.
You can probably guess my question… will combining the two different antifreezes cause a sludge to form from some chemical reaction?
Anyone else ever hear of this?
The “red antifreeze” is GM Dex-cool or Dexcool. I’m not sure on the spelling. This is in fact a known issue. By itself, the red stuff is supposed to last a substantial period of time. If contamined with the normal green stuff, the red stuff fails at an accelerated rate, which does cause some bad stuff to happen.
Googling “dexcool” turns up pertinent discussions:
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There’s a class-action suit:
http://www.cwcd.com/CM/MassTorts/MassTorts5.asp
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This page has advice for mechanics or fleet maintenance folks dealing with Dexcool-equipped vehicles:
http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.htm
Don’t mean to be a hardass, but did you check the radiator cap before filling the system? There should be instructions to use Dex-cool and an Orange dot on the cap indicating so.
I posed a similar question a while back.
It seems that the problem is with air exposed to Dex-cool. I don’t think your problem is with mixing, maybe you have a coolant leak, or a faulty radiator cap that lets air into the system. On some cars, the radiator is below the highest point that coolant travels in the engine. For this reason, there is a bleeder screw that would let air out of the system on the engine to prevent these problems.
Not on my '98 Chevy 5.7L P/U. I’m part of those class action suits due to $1,500 of damage Dexcool caused to my engine after changing it per GM’s recommended 5 years or 100,000. (which is now saying 150,000 miles)
I had the engine flushed and the coolant replaced with Texaco’s Dexcool after 4 1/2 years and less then 70,000 miles. Less than a year later my water pump leaked, my intake manifold leaked and my radiator was clogged. The pump and radiator had to be replaced and the intake manifold gasket had to be replaced. Not to mention the thermostat and radiator cap that I replaced.
The overflow bottle looked like a grayish-red soup.
The rule of thumb now is to change it every two years like the green stuff.
Here
And here
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