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I replaced the intake gaskets for the common LT1 intake wall leaks, but long story short it failed miserably.
I used the FelPro set with the included RTV tube to seal the walls. I removed all the old rtv, cleaned with brake clean, and reapplied. I made a nice thick bead on the front and rear using the whole tube, but it apparently didn't work.
It was fine for a few days but rapidly began leaking. It started dumping oil from both the front and rear of the intake. While running its running down all over the oil pan, oil filter, bell housing, and both cats.
What did I do so wrong? I've done plenty of china wall RTV gaskets on traditional sbc and sbf engines without issues...
Is there a trick to this I failed to grasp?
I went ahead and ordered some more gaskets and a new tube of Permatex Ultra Black to try again.
You can drill small shallow holes all along the china wall top and bottom and rough up the surfaces. Also once you put the rtv on just snug down the intake bolts-let it sit overnight, then torque it down. It is a pita when they leak!
It's possible the kit you installed was old and the included RTV lost its adhesivness.
It used to be recommended to dimple the china wall with a center punch to give the RTV something to grip to. Right Stuff was also the RTV of choice but I had good luck with Ultra Gray.
The recommendation of doing the final torque after the RTV has cured overnight is a good idea.
After cleaning, use "The Right Stuff" to build up a 3/8" bead along the front and rear walls. You can use a thin layer of the Ultra Black on the rest of the gasket.
Did you wait 24 hours for the rtv to cure? Otherwise I'm not sure how it can leak. Unless when you placed the intake down on the engine you had it offset and you pushed it into place, smearing the rtv. Or it wasn't torqued to spec. Good luck with round 2
It was allowed to cure overnight. But less than 24 hours.
I just got the intake back off. Something on the front China wall messed up, but the rear had a very nice spread and distribution of the RTV. Kinda scratching my head.
After cleaning, use "The Right Stuff" to build up a 3/8" bead along the front and rear walls. You can use a thin layer of the Ultra Black on the rest of the gasket.
Right Stuff is the best, period. I know Honda makes some pretty awesome stuff too.
But, dimple the china walls, and use the right stuff. Follow instructions. and torque manifold down per tech manual.
Looking at the pictures, was the manifold itself dirty, oily?
I just put the manifold on. I REALLY cleaned those surfaces well and dried/removed any possibility of residual oil/debris.
I put a nice fat bead of Permatex on the wall and finger tightened the bolts to squish the bead out.
I waited one hour per Permatex's directions and then torqued to spec in sequence over three passes.
Waiting until I get off work tomorrow to wrap up the harnesses and such. Should give the RTV plenty of time to cure before it sees oil.
I will update when I see some results.
Also I completely destroyed my oil pressure sender by accident when I pulled on it. That's some brittle 30 year old plastic...
Anyways the part store had another so I threw it on with some yellow gas-oil rated Teflon tape.
...should give the RTV plenty of time to cure before it sees oil.
-- the only thing i can add, is you CAN'T fast cure RTV with engine heat. the right stuff is the fast cure formula, but one should always follow the manufacturer's instructions. 3-stage torque and 24 hour cure - good job!.
Car fires up and runs fine. No immediate leaks that I can see. I'll update again after a week or so.
On another note, that new oil pressure sensor I got reads over 80 psi cold and LESS than 0 cold... How is that even possible?
I guess my oil has a vacuum on it
Leak Repair Massive Fail
