new intake manifold gasket
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 2,135
Likes: 0
From: Sebastian Florida
St. Jude Donor '06
new intake manifold gasket
I am putting new intake & valve cover gaskets on this weekend. 2 questions -
1st - How long will these tasks take
2nd - Any tips would be appreciated
Replacing because I have an oil leak somewhere and I am starting at the top and working my way down.
1st - How long will these tasks take
2nd - Any tips would be appreciated
Replacing because I have an oil leak somewhere and I am starting at the top and working my way down.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
This came up yesterday on another thread, too. Several posts, including mine, were put up citing some steps you should take to insure the new gaskets won't leak in the future.
They involve dimpling the China walls and the underside of the intake to allow the sealant you use (either sensor-safe silicone or the Right Stuff) to have something to "bite" into.
A thin layer of sealant around the ports - both intake and coolant - on both sides of the new gaskets help insure no leaks occur there.
Remember, leaks don't always show up right away; but only after the engine has gone through many heating and cooling cycles, during which the gaskets expands and contacts.
It's important not to have any oil residue on the mating surfaces too. Sealant won't, well, seal to oil/grease, etc.
You'll need to go over the bolt torque several times too, until they hold the torque setting. As the gaskets compress, torque on the bolts will lessen and this leads to new leaks. Same with headers, re-torque until the torque holds.
Also, there's a specific torque sequence for the intake manifold bolts. It differs from the "old way" of starting in the center and working toward the ends. There MUST be a reason GM changed the sequence so I recommend using it. Your Shop Manual should show the correct sequence.
I believe I posted the procedure that I recommend on the Tech Tips section of the Forum. If you can't find it, email me jakejr266@sbcglobal.net and I'll email it to you.
Hope this helps.
Jake
They involve dimpling the China walls and the underside of the intake to allow the sealant you use (either sensor-safe silicone or the Right Stuff) to have something to "bite" into.
A thin layer of sealant around the ports - both intake and coolant - on both sides of the new gaskets help insure no leaks occur there.
Remember, leaks don't always show up right away; but only after the engine has gone through many heating and cooling cycles, during which the gaskets expands and contacts.
It's important not to have any oil residue on the mating surfaces too. Sealant won't, well, seal to oil/grease, etc.
You'll need to go over the bolt torque several times too, until they hold the torque setting. As the gaskets compress, torque on the bolts will lessen and this leads to new leaks. Same with headers, re-torque until the torque holds.
Also, there's a specific torque sequence for the intake manifold bolts. It differs from the "old way" of starting in the center and working toward the ends. There MUST be a reason GM changed the sequence so I recommend using it. Your Shop Manual should show the correct sequence.
I believe I posted the procedure that I recommend on the Tech Tips section of the Forum. If you can't find it, email me jakejr266@sbcglobal.net and I'll email it to you.
Hope this helps.
Jake
