Dexcool/GM design claims another intake gasket

[childrd]

Finally got around to figuring out the digital camera and taking pictures of the failed gaskets on my Buick 3.8. I should have taken them sooner because the gaskets are not as deformed as they were when I did the job.

I don't have a web page so if someone wants to see them or post them let me know and I'll email them to you.

I never have found anything about what Mud mentioned regarding over torqueing of the bolts. I tightened them to the Haynes manual and switched antifreeze. I hope it lasts for another 5 years.

 

[Mud]

Just to clarify, I think that the lower intake bolts are too small and too few to adequately seal the intake. Nearly every bolt that I have seen on leaking 3.1 intakes had loosened.

I clean/chase the threads, torque to spec and also add some loctite to hopefully ensure a better seal.

 

[terminaldegree]

Just to clear a few things up:

the most common problem with the 3800 series II is the plastic intake manifold. Series I and III don't have this manifold, and all the supercharged cars don't have that manifold, either. F-body series II's [firebird, camaro] also don't have the composite intake.

I honestly don't know whether or not dexcool accelerated the failures. I'm running dexcool in my firebird, and some generic "all makes all models"' stuff in my lesabre. The "Dorman" replacement intake has been fine on our lesabre so far.

If you don't have this problem yet, and you own a 3800 series II, you'd be well advised to keep a CLOSE eye on your coolant level.

 

[Malaclypse]

I work at a GM dealership and this is an account of my direct experience dealing with 3100 and 3800 V6 engines using dex-cool.

The 3800 (3.8 V6) will have more coolant leaks from the upper intake than the lower. This is because two different materials are being used. Aluminum for the lower intake and a plastic/composite upper intake. The difference in materials means that there is a difference in expansion rate between the two. Over time this caouses the Upper Intake gasket to wear because its sliding between two surfaces for each warm-up and cool-down cycle the engine has.

Recall 03034 has only to do with the throttle body nuts. I've never seen a leak from there.. but whatever.

The 3100 is a whole other story. Dex-cool did not cause the failure. Every single 3100 engine that I've changed intake gaskets on has never come back. That's more than 50 cars for myself alone. Every car was filled with dex-cool. The cars that had a dex-cool/ethylene glycol mix were flushed with water and filled with a 50/50 dexcool mix.

None of them have come back. Even three years later.

The point is that Dex-cool does not cause failures. The 3800 has its design flaws. The poor design of the gaskets for the 3100 has been fixed with new gaskets and revised torque specs.

So before anyone goes on pointing fingers at the General for these two issues... Stop and think about how many Fords have burned down a family's home... =p

P.S. I know this is my first post... but I've been trolling since late last year. (Considered posting a few times). I just now got around to it.

 

[thrace]

quote:

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Every single 3100 engine that I've changed intake gaskets on has never come back. That's more than 50 cars for myself alone. Every car was filled with dex-cool. The cars that had a dex-cool/ethylene glycol mix were flushed with water and filled with a 50/50 dexcool mix.

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I understand (maybe not correctly) that for the 3100 there is a new gasket, new bolts and that sealer must be used on the bolts.
Do you know whether newly made 3100 engines incorporate the fix? Starting what year?
Is there a description somewhere on the internet that is publically available on how a DIY person could repair their own 3100? Thanks.

 

[Elroy the Unique]

quote:

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Originally posted by Malaclypse:
The 3800 (3.8 V6) will have more coolant leaks from the upper intake than the lower. This is because two different materials are being used. Aluminum for the lower intake and a plastic/composite upper intake. The difference in materials means that there is a difference in expansion rate between the two. Over time this caouses the Upper Intake gasket to wear because its sliding between two surfaces for each warm-up and cool-down cycle the engine has.

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Is there any possible preventative maintenance that can be done? I am thinking about adding some Bar's Leak (black oily version) addative when I change the cooland out in order to shore up any worn gasket area.