DeathCool advice on 2001 Impala

Hello All: My 2001 Impala 3.8 just turned over 69K miles. It will be 7 years old on Dec 2007. I bought the car when it was about a year old with 10K
miles. When the car was four years old and about 40K miles, I drained the 'DeathCool' coolant and replaced, and included a new AC Delco radiator cap. I burped the car at the thermostat housing, and have had no problems, so far. Today I took the radiator cap off, and noticed some sludge on the cap. I have heard that this is an early warning that the intake manifold gaskets are about to fail, and the sludge is a result of air in the coolant, or 'over extended' deathcool. So, should I change the coolant now (again)? Should I just wait a few days for the manifold gaskets to fail? Any advice is appreciated. Take care, Bill
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Ok, you replaced, with?

You shouldn't have refilled with deathcool, first of all, and second of all, yes this could indeed be the start of your LIM's failing.
-GV
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Sludge usually means air in the system.
Lots of info on the rad cap and other stuff in the following links,
http://www.imcool.com/articles/antifreeze-coolant/dexcool-johnbrunner.htm
http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.htm
http://www.imcool.com/articles/antifreeze-coolant/index.html
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Hmm... is there a single place that lists all the vehicles that have this problem?
I have a 95 GrandPrix that mixed the oil air and water. First hint I had of a problem was 'goo' getting in the digital EGR valves and a check engine that would come and go, usually turning on after the car was run about 25-30 minutes and I decelerated.
Anyway, it finally croaked. I was lucky it didn't hydrolock, and was salvagable. Flushed and flushed and flushed after rebuild. Now the thing runs fine. (Just put a new condenser in the thing, and it even makes ice cubes!)
But I'm wondering about my 99 Intrigue with 3.8. It's got 155K miles on it and runs fine (other than no AC anymore, so I guess I'm gonna have to tackle that eventually). At least for now.
Should I be woried?
Mike
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Worried? No. All GM 60 degree engines suffer the problems of intake manifold gaskets. Look for signs of leakage around the gasket seal areas on the front and rear of the block. If you see stains, get a gasket kit and install it.
--

-Mike-
snipped-for-privacy@alltel.net
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Mike,
The engine in Mike Y's Intrigue is the 90 degree 3800 Series II engine. The major problem with these engines regarding gaskets is caused by the EGR passage warping the upper intake manifold, which permits coolant to leak into the internals of the engine. The repair involves replacing the upper intake manifold (which is a plastic casting). GM has redesigned this part more than once to alleviate this problem, and there are aftermarket replacements available that some mechanics tell me are superior to even the redesigned GM part.
Mike Y, keep REAL CLOSE track of any coolant usage. If the engine begins to use coolant and you cannot find any external leaks, it is time to have the engine looked at. If the warped upper intake issue is caught early no long-term damage will be done to the engine.
Regards, Bill Bowen Sacramento, CA
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Thanks for the tips.
The Olds actually was a fire car. When fairly new, about a year or so, it had a major engine fire and was junked. Otherwise the car was fine. The salvage yard owner routinely picks cars like this, mixes and matches to make a really nice one, then gives them to his wife to drive for a year or so. Then another car, then another...
However, she liked this one so much she kept it for almost 5 years, then finally decided to get another. As a result, I got it at about 120,000 miles in excellent shape.
I'm not exactly sure what all the original damage entailed, but I'm fairly certain anything plastic was replaced in the engine compartment.
Would it make any difference if I could find out what parts were replaced? I'll keep an eye on it in any case.
Mike
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William H. Bowen wrote:

What you think, when ready to drain dexcool, just replace with the new Prestone 150k miles green coolant. This way avoid all problems associated with dexcool. On my 2000 buick regal, I am thinking to make a switch.
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I'm switching to either green (in my older vehicles, 10+ years) or universal coolant in my newer vehicles.
-GV
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Since I had to drain my van last week to remove the radiator (to replace the air conditioner evaporator core), I replaced the coolant with Prestone. Surprisingly it wasnt green. It was a fluorescent yellow, and is claimed to be compatible with all other antifreezes.
In fact, every brand of antifreeze on the shelves in WalMart and Autozone seemed to be of the total compatibility variety. I suspect these are HOAT compositions, but dont know for sure.
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