Oil Leak source from intake?
Thread Starter
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Oil Leak source from intake?
OK will someone please explain the reason for the intake oil leak that is common on LT1s. I have the gaskets and am going to change them pretty soon so any additional tips on that would be appreciated. Thanks
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The intake gaskets seem to be a problem with chevy's. If you do a search, one of the best solutions is to:
1) Take a center punch and dimple the front of the engine block and the rear of the block with the center punch. This is the section between the heads. Also dimple the intake manifold in the same areas.
2) Use the Right Stuff from Permatex as your gasket sealer on the gaskets. On the front and rear of the block run a 3/8" bead across the area that you dimpled.
3) Carefully place the intake on the gaskets without shifting it from side to side or front to back. It helps to have another set of hands and a couple of center punches to use as guides to line up the holes as you set the manifold in place.
4 Torque your intake and let it sit 24 hours before running.
This should solve the problem.
1) Take a center punch and dimple the front of the engine block and the rear of the block with the center punch. This is the section between the heads. Also dimple the intake manifold in the same areas.
2) Use the Right Stuff from Permatex as your gasket sealer on the gaskets. On the front and rear of the block run a 3/8" bead across the area that you dimpled.
3) Carefully place the intake on the gaskets without shifting it from side to side or front to back. It helps to have another set of hands and a couple of center punches to use as guides to line up the holes as you set the manifold in place.
4 Torque your intake and let it sit 24 hours before running.
This should solve the problem.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
the leak is caused when the RTV that seals the intake to the block blows out.
Some pointers:
1) Get a can of Copper Gasket Spray. That is nice to add to the gaskets themselves.
2) Use Copper RTV. It's much more oil resistant and heat resistant.
3) Using a drill with a small bit, drill a number of dimples into both the block (lay a rag out to capture the frags) and the intake on the mating surfaces. This will allow the RTV to bite into the metal.
4) Use more RTV then GM recommends. A wider, thicker bead (but not much more, maybe 20%) will hold better then that puny thing GM suggests.
5) Allow the intake to cure for atleast 18 hours before starting the car. If not, crankcase pressures will cause the wet RTV to blow out.
Some pointers:
1) Get a can of Copper Gasket Spray. That is nice to add to the gaskets themselves.
2) Use Copper RTV. It's much more oil resistant and heat resistant.
3) Using a drill with a small bit, drill a number of dimples into both the block (lay a rag out to capture the frags) and the intake on the mating surfaces. This will allow the RTV to bite into the metal.
4) Use more RTV then GM recommends. A wider, thicker bead (but not much more, maybe 20%) will hold better then that puny thing GM suggests.
5) Allow the intake to cure for atleast 18 hours before starting the car. If not, crankcase pressures will cause the wet RTV to blow out.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
When I did my intake I let it stand for over 24hrs after torquing the base to spec. The next day I hit all the bolts again and then installed the rest of the intake and accessories.
