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Dan, Auto Technician
Category: Chevy
Satisfied Customers: 3490
Experience:  GM Mark of Excellence/ Service Guild Participant with 13 years experience, ASE Master Certified
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Chevy: 3.4L..intake manifold gasket..leaks..the head gaskets

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what is the latest info on the chevy 3.4L intake manifold gasket leaks? are the head gaskets also prone to the same problems as the intake manifold?
#03-06-01-010B: Engine Oil or Coolant Leak (Install New Intake Manifold Gasket) - (Oct 24, 2003)

Subject:Engine Oil or Coolant Leak (Install New Intake Manifold Gasket)

Models:2000-2003 Buick Century
2002-2003 Buick Rendezvous
1996 Chevrolet Lumina APV
1997-2003 Chevrolet Venture
1999-2001 Chevrolet Lumina
1999-2003 Chevrolet Malibu, Monte Carlo
2000-2003 Chevrolet Impala
1996-2003 Oldsmobile Silhouette
1999 Oldsmobile Cutlass
1999-2003 Oldsmobile Alero
1996-1999 Pontiac Trans Sport
1999-2003 Pontiac Grand Am, Montana
2000-2003 Pontiac Grand Prix
2001-2003 Pontiac Aztek
with 3.1L or 3.4L V-6 Engine (VINs J, E - RPOs LG8, LA1)


This bulletin is being revised to change the model Information. Please discard Corporate Bulletin Number 03-06-01-010A (Section 06 - Engine).


Some owners may comment on an apparent oil or coolant leak. Additionally, the comments may range from spots on the driveway to having to add fluids.


Intake manifold may be leaking allowing coolant, oil or both to leak from the engine.


Install a new design intake manifold gasket. The material used in the gasket has been changed in order to improve the sealing qualities of the gasket. When replacing the gasket, the intake manifold bolts must also be replaced and torqued to a revised specification. The new bolts will come with a pre-applied threadlocker on them.

Object Number: 190523  Size: SH
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Notice: An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.

Diagonal bolts may require a crows foot to tighten.


  1. Tighten the vertical lower intake manifold bolts (1) to 7N·m (62 lb in).
  2. Tighten the diagonal lower intake manifold bolts (2) to 7N·m(62 lb in).
  3. Tighten the vertical lower intake manifold bolts (1) to 13N·m(115 lb in).
  4. Tighten the diagonal lower intake manifold bolts (2) to 25N·m(18 lb ft).

Parts Information

Part Number




Intake manifold Gasket



Intake manifold bolt - short



Intake manifold bolt - long


Parts are currently available from GMSPO.

Customer: replied 8 years ago.
Reply to Dan's Post: In my question I also asked about the head gaskets. Do they have the same problem and should I go ahead and repalce them as well?
I only replace the head gaskets if they are leaking and/or the engine is overheating. The intake gaskets are more prone to leak and cause coolant loss or overheating due to the coolant loss. But if they weren't taken care of then you would definitely do some damage to the head gaskets and maybe the cylinder heads if severe enough. To answer your question, only do the head gaskets if blown or causing an overheating/driveability issue.
Customer: replied 8 years ago.
Reply to Dan's Post: OK, the car is not over heating, or running rough so I am assuming the head gaskets are fine.

There is a bit of milky white subtance on the oil filler cap which is sure sign that water/coolnat is getting into the engine.

futher checkin on web sites bulletin boards reveal that there are now new style intake gaskets both by GM and FEL-PRO. also anther place called D&S engines that say they fix this problem for good. as others have had to replace both more than once. In addtion the problem is caused by the original DEX-COOL that GM recommended for the engine. I have also heard that the New DEX-COOL is now reformulated to not cause the problem any longer.

Can you tell me whta you know about the new gaslets and the new type DEX-COOL?

The new gaskets seem to be working as I haven't had any intake jobs come back. As for the new Dex-cool, have not used it so can't tell you either way. I can tell you if you are having a problem with the coolant gelling and crystalizing in the coolant system you may want to consider going to green coolant. It has much better cooling properties and doesn't do anything near the damage Dex-cool does.
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