Intake Gasket Failure Question

On the contrary. GM says Dex-Cool is god's gift to man. They wouldn't still use it otherwise. Any problem is the owner's fault for not checking the coolant's quality with a refractometer often enough. (according to the AC Delco guy that taught the last after-work training seminar I attended.) GW

No, GM does not think that Dexcool has anything to do with gasket failures. The intake gasket failure is due to a poor design that relies on low clamp loads and the fact that a technician ought to know how to torque bolts and use loctite in these particular applications.

Intake gasket failures on GM 60 degree engines have been happening since they started making the engines in the mid 80's. When they first came out in the X-bodies and A-bodies....we were doing intake gaskets all the time. Same problem.....coolant would get in the engine oil. Different style of gasket....same basic end result...coolant in oil. There has also always been a problem with oil leakage from the RTV end gaskets. This is due to two problems.....poor preparation of the surfaces by the technicians....and the fact that RTV gaskets will inevitably leak no matter what you do.

Ian

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My refractometer only shows freeze point...

Which would, of course, be higher if the Dex-Cool to water ratio was higher or lower than ideal. The statement from the Delco rep, may or may not be hogwash, but supposedly.... If the Dex-Cool to water mix is not within a few points of the 50-50 range, the mixture becomes VERY acidic, and THAT is the owners fault for not maintaining the 50-50 mix, not the Dex-Cools fault. The main dilution of the ideal mix comes from air in the system. How does air get in? Bad radiator cap. GM never said they were five year caps, just five year coolant. GW

How can you blame it on the technicians or poor preparation on a factory new engine? It is GM's fault - pure and simple. A design that uses low clamping loads combined with gasket materials that cannot seal under low clamp load conditions is poor design, no ifs, ands, or buts about it.

Not fixing the root problem is the result of the bean counters looking at the cost to repair the desihn vs the cost to repair under warranty, taking the average lifespan into account. Simply put, they figure it is cheaper to replace a few thousand gaskets a year than to redisign the engine.

What they fail to take into account is the loss of sales due to customer dis-satisfaction and anger.

And they wonder why they couldn't sell enough Oldsmobiles to make it worth while retaining the marque - and now either Pontiac or Buick (or possibly both) may well follow suite.

Used to be the cry was "kill all the lawyers".. Soon it will be "kill all the accountants". Between accountants and lawyers, manufacturing jobs are relentlessly being driven out of the USA , and close behind, out of Canada as well.

I never read that GM said that about DeathCool. I don't belive it and think it false information. The problem has been around a lot longer than 10 years. IMO, the 60 degree engine is a poor design for intake/head mating. You might want to do some reading on the subject.

When I was having problems I re-torqued the intake manifold bolts. There were loose bolts. This seemed to have done the trick. This also worked on the valve cover the oil pan and a part around the output shafts on the transmission.

I was talking about the RTV section of the gasket. Eventually they all do leak, but I and other techs that I know that take the time to use RTV properly don't see the intake gasket back leaking from the RTV very often. But the one's that dont take care, usually are re-doing them.

The entire engine design is suspect....but you are right, bean counters will do us in.

Ian

I am a member of this club, 98 Lumina 3.1 once when it was under warranty and now again at almost 80k! I plan on replacing the coolant fluid with the good old fashion Prestone green antifreeze. Does anyone think all this trouble may be from the new dex coolant or just crappy design?

After clean> I am a member of this club, 98 Lumina 3.1 once when it was under warranty

In my experiance Dexcool is still far better if the leaks are repaired correctly. When I remove plastic gaskets that have been running conventional green coolant I find most of the plastic material is missing and whats left of the gasket is very brittle. I also find a lot of pock marks in the aluminum which will never re-seal without good RTV. However the rubber beads built into those gaskets are usually swelled up which is the "only" advantage the silicon based coolants give you. (until they blow out from lack of plastic material)

Dexcool contains a plasticizer which softens up the plastic gaskets ever so slightly. For the 60deg motors this is a huge problem considering they dont have a very good clamping load on the gaskets and the gaskets are taller and thinner around the passages. For the 3800's lower intake gaskets this isnt much of an issue.

I've had the top part of the engine off a couple times replacing injectors and the lower manifold gasket. There was very little corrosion anywhere. I have changed the Dexcool on 2 1/2 - 3 yr. intervals and changed the pressure cap to one having a spring-loaded relief per item 4 in this article: Dexcool Article So, based on my observations I'd choose crappy design. Ian has posted info recently on a new gasket released and fastener specs for this engine family. Don't know if there's enough history yet to know if it fixes the problem. My vehicle was a 98 Pontiac Montana.

Nice dexcool article you mentioned.

I have a question about coolant recall for my 2000 Buick regal (LS, nonturbo). I have been changing dexcool every year and it has 65000 miles. GM is sending me recall notice every 3 months to care recall. The recall will expire in July 2005.

My questi>

WOW I never realized all the trouble with these engines. I am amazed they would let this known problem continue for so long.

Why not? The small block Chevy camshaft problem went on for decades...

What problem are you referring to?

Improperly heat treated camshafts.

Did hundreds in and out of warranty, as I'm sure Ian did also.

Yes...many of them never even made into the shop for a PDI.

Ian

heh-heh-heh.... ;-)

Gosh, any wonder why Toyota, Honda, Nissan and even Hyundai are kicking the

John