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Hi all, I am addressing the intake manifold gaskets and sealant in the front/back of the engine causing major oil leaks on my 1995. This is the first sort of big service I'm doing to the car, and I don't want to have to do this twice. Here are some questions I have:
1. How clean do the mating surfaces have to be? I've wiped quite a bit using brake cleaner and the surfaces feel very smooth to the touch, but they aren't perfectly shiny (see pics). Could this affect sealing?
2. What is the best way to clean the intake manifold? It's completely filled with carbon.
3. Should I try and wipe out the intake ports a little bit, or just leave them be to avoid any risk of dropping debris into an open chamber?
4. While the intake is off, are there any other things that I might want to address? I've already cleaned the throttle body and EGR, and I'm sending the injectors to a shop for cleaning.
5. Any tips for sealing the front and rear? I have black Permatex RTV.
6. Is it okay to leave the intake off for a day or two if necessary? I have the ports taped closed and a towel over the valley.
I guess if you are concerned with the manifold itself you could always take it to a machine shop and have them hot tank it. Do a search here. Many posts on this china wall methods. Dan
that intake and china walls are good to go, the bottom of the intake is the shield for the egr cross over. its usually hard and crusty from hot exhaust gas passing through under the shield on the manifold, you can either remove the shield and 1 - hot tank it or 2 - scrape it and wash it down with brake parts cleaner and air dry then reassemble.
Get a nice fat bead on the front and back. It's awkward but try your best to set it down on the engine, not slide it into place and risk smearing/ wiping the rtv off. Not fun doing it twice. Also don't forget after you torque it down, it needs 24 hours to cure before start up.
that intake and china walls are good to go, the bottom of the intake is the shield for the egr cross over. its usually hard and crusty from hot exhaust gas passing through under the shield on the manifold, you can either remove the shield and 1 - hot tank it or 2 - scrape it and wash it down with brake parts cleaner and air dry then reassemble.
Yea I'm gonna bring it to a machine shop tomorrow and see what they can do. I got a lot of brake clean and other solvents in most of the small passageways, and there's just too much crud I can't reach. I don't want to clean it halfway and have something break loose when running.
I would suggest an "advanced search" for China wall. There are very detailed posts that will help you. Some show how to micro dimple the China wall with a pointed punch to help hold the sealant. Some say "the right stuff" is the best sealant. Some say to lay the bead and only finger tight the bolts and wait a period of time before torquing. A lot of good info. Dan
Intake Manifold Questions
