Old Roadtrek 190 - 5.7 L V8 - intake manifold gaskets?

[Mike]

I moved this one over from the "Vans" page for better visibility by more people
because it is an insidious little problem with our, and possibly other Chevy vans.
I noticed I was using a little more coolant than normal over the past month or
so, and also noted a small stain on the driveway last week after a local road trip.
Took it in to local GM dealer today, and they say it's the intake manifold gasket.
The repair estimate is around $1000. Includes a new serpentine belt (woohoo!!!! ).
Of course I asked about the relationship between Dexcool and these problems.
Apparently there hasn't been a proven correlation between Dexcool and the intake
gasket deterioration, according to the shop guy. He also said that if you flush your
system at least every 3-4 years, you shouldn't have any problems. I see where
using the green coolant instead, and not flushing it every few years, is just as bad
for your gaskets, etc.. Maybe it's not just Dexcool?
My van has 180,000 kms on it. The coolant was flushed in Fall 2009 by me.
It might have been the only flush since new, as I'm the 3rd owner.

Comments? Am I correct in assuming this is more widespread than just my vehicle?
Is there any point in switching to the general purpose "green stuff" I see mentioned
on various blogs and websites regarding this issue? Getting away from DexCool?
I just called the dealer ship back and asked them to flush me, and replace the Dexcool
with the "green stuff". They said "no problem", almost as if they were relieved that
I called back with my request. Peculiar?

[Ron J. Moore]

Mike, I read a great deal of info regarding Dex-Cool at the Express_Savanna Vans at Yahoo. I have a '98 Chevy P/U with the 5.7 and well on its way to 200K. I have only used Dex-Cool and have never had a problem. But I remember seeing this discussion and wondered about it.....but that was the end!! Safe travels.

[Mike]

Hi Ron,
Thanks for your input. So it's still a controversial subject on more than one blog, to say the least?
I'm guessing that there must be something to it, and that it's more than just the grumblings of
a few dissatisfied GM owners, who've had reason to replace the gaskets on a small cross section
of GM engines, with a similar theme, intake manifold gaskets, and DexCool, and all at relatively
low mileages it seems.
You might want to have a look at Booster's comments about this, on the "GM Owners" thread under
"The Vans" section on this forum.

Thanks.

[g1g]

I have a friend who was having problems and a dealer mechanic said the dexcool was eating the intake manifold gasket. He had seen many of them and also said when using dexcool do not make the mix stronger than 50/50. Susposedly if you do it will eat the gasket but they say less than 50/50 is safe. We googled dexcool problems and there is a ton of them. I heard some engines are recalled but if I remember right they are all small 4 or maybe 6 cylinder ones no v8 ones. My solution is get rid of dexcool and put in the good old fashion stuff. If your leek isn't to bad try flushing it out and put in block sealer. What do you have to loose?

[Mike]

I have asked the dealership to go ahead with the repairs, and to switch me
to the non-DexCool coolant after a hopefully thorough flush. There is also some
mention of not mixing Dex with the "green" glycol coolant. Apparently it's likely
to cause sedimentation and can gunk up rads and hoses and water pumps.
So it's too late to try any home remedies now. Thanks for the comments and
further info on this nasty little problem.
I guess if you're not sure if your GM engine's coolant has been flushed, you might
want to look into it, before you have any problems. I now suspect I may have
inherited the problem from the previous owners, but when you buy used, it's a
chance you take, I guess.
I've owned other GM vehicles, all pre-DexCool, and never heard of, or had this
sort of problem.
It's also apparently too late to pursue it with GM. Chapter 11 does have some perks.

[Mike]

Done. Replaced gasket and sundry shop supplies including switch to the "green stuff"
which is now the "yellow stuff". I had a quick look under the hood when I picked up
the van, and was surprised to see yellow liquid in the recovery reservoir. I had to ask
and was told it's now yellow. I also asked about the water pump and was told no signs
of problems with it, or any other ancillary fallout.
So parts $200,
labor $700,
tax around $120.
Total just over $1000.
Oh, well........

[Mike]

My yellow stuff turned slightly amber over the weekend.
I have since called the dealership and been told it is possible some Dexcool
wasn't completely flushed out, but that it shouldn't cause any problems.
I have dated and timed and added the service agent's name to my record of the call,
just in case.
Next oil change, or maybe the one after, and I'll have it flushed and changed again.
"On spec".

[Johnny R]

Oh man, you should read the GM forums on this intake gasket problem. The dealer repaired that problem on my '99 Malibu 3.1L at 75,000 km ( in 2002) under a customer goodwill policy, but only after I was very aggressive about it with letters to the dealer and GM, and some other things. I doubt they would do the same at 178,000 km though, on an 8 year old vehicle. Afraid you'll have to suck it up.

[Mike]

Yup.