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#558778 - 01/03/05 08:00 AM Is the GM 3.1/3.4 V6 inherently flawed?
pbm Offline


Registered: 04/19/04
Posts: 5214
Loc: New York
I posted this question as part of my response on another thread and have't gotten any responses.
I wanted to know if these motors have inherent design flaws which cause the notorious intake-manifold gasket leaks or is it the gasket material or is it the fastening method or did these problems pop up when Dexcool came on the scene.
Is there a way of making the repair so as to avoid a reoccurence of the problem (ie: using Loctite on the fasteners etc..) I would appreciate any available information on this topic. Thanks

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#558779 - 01/03/05 08:10 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
Marlin Offline


Registered: 11/13/04
Posts: 189
Loc: Raleigh, NC
No it is NOT the engine. From what I have read it is when GM changed materials for the lower intake manifold in that it flexed differently then the engine/heads did. So one would expand faster then another and using the old style gaskets caused them to be rubbed back and forth. Over time they just gave up, the gaskets.

That is why a simple fix is to use a updated gasket set that allows a little movement.

Also the 3.8L had some problems with this also for a short while, but it is a 90degree motor so the movement was not as bad as with the 60degree 3.1 motors.

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#558780 - 01/03/05 08:30 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
pbm Offline


Registered: 04/19/04
Posts: 5214
Loc: New York
Marlin: I'm glad to hear that. Do you know when/if GM started to use this better (more flexible) gasket. I've done a google search and there seems to be a lot of conflicting information. I would still like to hear from any mechanics who have tips on doing this repair properly so that it doesn't reoccur. Thanks

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#558781 - 01/03/05 08:31 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
jthorner Offline


Registered: 07/11/03
Posts: 1130
Loc: California
I would have to say that it is indeed a flawed design. GM vehicles with the 3.1/3.4 family of engine have had this problem for over 10 years with at least three different gasket designs.

Whether or not the latest gasket (out last year) has finally fixed the problem or not is still open to question as the newest design has not been out long enough to know if they are failing or not.

John

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#558782 - 01/03/05 08:37 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
Drew99GT Offline


Registered: 10/11/02
Posts: 20692
Loc: Colorado Springs
quote:
Originally posted by jthorner:
I would have to say that it is indeed a flawed design. GM vehicles with the 3.1/3.4 family of engine have had this problem for over 10 years with at least three different gasket designs.

Whether or not the latest gasket (out last year) has finally fixed the problem or not is still open to question as the newest design has not been out long enough to know if they are failing or not.

John

It is absolutelly a flawed design. Find some pictures of one of those motors opened up; you'll see how the pushrods have to go through the gasket/up the side of the heads (instead of through the cylinder heads, which makes it tougher to lay the lower manifild in place and not disturb the gasket. Also, the gaskets were cheaply made, and the location of the fastners won't place an equal clamping load on the gasket. The spot where the load is least is on the ends of the heads; right where the cooling jacket goes from the heads into the intake manifold.

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#558783 - 01/02/05 10:03 PM Re: Is the GM 3.1/3.4 V6 inherently flawed?
pbm Offline


Registered: 04/19/04
Posts: 5214
Loc: New York
quote:
Originally posted by Drew99GT:
quote:
Originally posted by jthorner:
I would have to say that it is indeed a flawed design. GM vehicles with the 3.1/3.4 family of engine have had this problem for over 10 years with at least three different gasket designs.


John

It is absolutelly a flawed design. Find some pictures of one of those motors opened up; you'll see how the pushrods have to go through the gasket/up the side of the heads (instead of through the cylinder heads, which makes it tougher to lay the lower manifild in place and not disturb the gasket. Also, the gaskets were cheaply made, and the location of the fastners won't place an equal clamping load on the gasket. The spot where the load is least is on the ends of the heads; right where the cooling jacket goes from the heads into the intake manifold.
Drew:
I'm not doubting you but I don't recall these problems with the 2.8 from which these engines were spawned. Does the new 3.5 in the Malibu have these same flaws?

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#558784 - 01/02/05 10:24 PM Re: Is the GM 3.1/3.4 V6 inherently flawed?
Marlin Offline


Registered: 11/13/04
Posts: 189
Loc: Raleigh, NC
quote:
Originally posted by pbm:
quote:
Originally posted by Drew99GT:
quote:
Originally posted by jthorner:
I would have to say that it is indeed a flawed design. GM vehicles with the 3.1/3.4 family of engine have had this problem for over 10 years with at least three different gasket designs.


John

It is absolutelly a flawed design. Find some pictures of one of those motors opened up; you'll see how the pushrods have to go through the gasket/up the side of the heads (instead of through the cylinder heads, which makes it tougher to lay the lower manifild in place and not disturb the gasket. Also, the gaskets were cheaply made, and the location of the fastners won't place an equal clamping load on the gasket. The spot where the load is least is on the ends of the heads; right where the cooling jacket goes from the heads into the intake manifold.
Drew:
I'm not doubting you but I don't recall these problems with the 2.8 from which these engines were spawned. Does the new 3.5 in the Malibu have these same flaws?

I was about to say the same thing. I have taken apart a PILE of 60 degree chevy motors from the early Carb 2.8L to the current 3.4L version. They have ALL had the same stle pushrod head style.

Agaian the problem lays in the new intake material and gaskets. When I have replaced the intake gaskets on a 3.1/3.4 I have used fel-pro's and have had no problems. Juts make sure the manifold is straight and clean.

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#558785 - 01/02/05 10:29 PM Re: Is the GM 3.1/3.4 V6 inherently flawed?
Marlin Offline


Registered: 11/13/04
Posts: 189
Loc: Raleigh, NC
Here is a story about the Fel-Pro gaskets...

http://www.theautochannel.com/news/2004/10/14/252583.html


"Available through Fel-Pro suppliers across North America, the brand's latest gasket innovation ensures a lasting seal on millions of domestic engines that rely on extended-life coolant and were factory-equipped with rigid nylon and molded rubber-type intake manifold gaskets."

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#558786 - 01/03/05 05:39 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
Mickey_M Offline


Registered: 08/13/04
Posts: 1001
Loc: Baltimore
quote:
Originally posted by pbm:
I posted this question as part of my response on another thread and have't gotten any responses.
I wanted to know if these motors have inherent design flaws which cause the notorious intake-manifold gasket leaks or is it the gasket material or is it the fastening method or did these problems pop up when Dexcool came on the scene.
Is there a way of making the repair so as to avoid a reoccurence of the problem (ie: using Loctite on the fasteners etc..) I would appreciate any available information on this topic. Thanks

I suppose it depends on what you mean by "design flaws".

Every design has compromises, and therefore every design has weaknesses.

www.carquest.com/techbulletins/gaskets/gskms15704.pdf

http://www.geocities.com/gmgasket/

http://www.autosafety.org/uploads/SB-10001282-8175.pdf

http://www.consumeraffairs.com/automotive/gm_intake_manifold.html

http://www.snopes.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=70;t=000401;p=0

http://www.jasperengines.com/pdf/GM_3.1_3.4_TB.pdf

As you can see from the above GM has revised the intake manifold gasket for these engines and at least one aftermarket vendor has a "fix" gasket available.

That seems to indicate that at least some percentage of these engines develop oil and/or coolant leaks at the intake manifold.

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#558787 - 01/03/05 07:17 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
doitmyself Offline


Registered: 06/03/02
Posts: 4719
Loc: MI
This is interesting stuff, gentlemen. I believe there are 7 or 8 states that have a class action regarding the GM leaking manifold. But, I thought that they were blaming the Dex-cool, not the engine(correct me, if I am wrong).

And.....some petitions are just blaming the gasket.

Now you are saying it is an engine design flaw!

[ January 03, 2005, 11:24 PM: Message edited by: doitmyself ]

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#558788 - 01/04/05 01:40 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
JohnBrowning Offline


Registered: 05/01/03
Posts: 9448
Loc: USA
The 2.8,3.1,3.4 and 3.5 are all very poor engine designs! They are ultra cheap to produce and that is why they are still being used. They do not offer smooth running, broad power band or lots of power! They are not a high output engine either. Soon most of the 3.5 are going to be made in China and shipped back to the USA. Currently the Eqinox has the Chinesse sourced 3.5.

GM has redesigned the gaskets, revised the thread sealant to be used, switched out the bolts and torque patern multiple times. Even the mighty 3.8 has been plagued by problems due to their bumbeling! When they switched the Buick V8 from an aluminum intake manifold to a plastic one all heck broke lose. An otherwise perfect engine was devolved and plagued with coolant leaks. The 3.8 is now undercontrol according to GM thank goodness!

If you are looking at 2004 or 2005 GM products try to get one with the Buick 3.8. They have solved the upper intake manifold issues on it and it should once again be a 300,000 mile engine!

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#558789 - 01/04/05 04:24 PM Re: Is the GM 3.1/3.4 V6 inherently flawed?
T-Keith Offline


Registered: 01/20/04
Posts: 4865
Loc: MN
John all 3.8s are a 500,000 mile engine. A few had problems with the plastic intake, but it was a batch problem not a design one.

The Equinox has the old 3.4 that's why it's made in China, because they still use it there. All 3.5s are made in NA, they have changed much of the design and they are making 200hp now. While the 60degs are no 3.8, they are still good engine and I've had a couple with 150,000+ miles. They've solved many of the problems and are now making lots of power.

-T

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#558790 - 01/05/05 12:25 AM Re: Is the GM 3.1/3.4 V6 inherently flawed?
wlkjr1951 Offline


Registered: 04/19/04
Posts: 64
Loc: Georgia
quote:
Originally posted by JohnBrowning:
The 2.8,3.1,3.4 and 3.5 are all very poor engine designs!

Please don't leave out their 2.3 Quad Four. I had one of these in a Grand Am and it would fly. Great car for the first 125,000 miles. Then the first head gasket went. Expensive. Replaced it twice before selling it with over 300,000 miles on it.

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