Oil leak on upper rear of motor

If engine oil is running down the top of your bellhousing, than your leak is coming from the rear "end rail", the ridge at the top of the lifter valley between the two cylinder heads.

Leaks here are very common when people use the supplied cork end-rail gaskets that come with many intake manifold gasket kits. Some people have some success in getting those cork end rail gaskets to seal, but most racers, performance engine builders, and even aftermarket intake manufacturers themselves recommend throwing away those end rail gaskets and using a thick bead of RTV silicone instead to prevent leaks.

It is possible to develop a leak even when using RTV back there, if the person applying the RTV isn't careful, and fails to make a nice thick unbroken bead of silicone.

You may need to remove the lower intake and install new gaskets/RTV.

My tips for installing intake manifold gaskets, leak free:

1. Using a gasket scraper, make sure the front and rear end-rails, along with the cylinder head gasket mating surface, is as flat and clean as possible. Razor blade style gasket scrapers can be handy for removing thin or hard to remove caked on gasket material.

2. You can use, though it is not mandatory, a gasket sealant like Edelbrock Gasgacinch. It serves two purposes. It helps ensure the gaskets seal between the intake and head surfaces, and also when removing the intake in the future, it helps to keep the gaskets in one piece, reducing the chance of stuck/torn gasket material left on the heads or intake, which quickens cleanup time. It has a brush on the inside of the lid, and you simply brush the sealer on both sides of the gasket, let it tack up for a few minutes, and then put the gaskets on the heads intake mating surface.

3. Also not necessary, but it helps: Cut the heads off of four extra intake bolts, or cut four pieces of threaded rod, and thread them into the four farthest corners of the intake bolt holes in the heads. This will allow you to lower the lower intake onto the gaskets without any risk of slipping/sliding or mis-aligning the gaskets.

4. If your gasket set included cork end rail gaskets, throw them away. Instead, use Permatex Black RTV or "The Right Stuff" RTV and lay down a thick bead across both end rails. Go ahead and start the bead by dabbing the RTV on one intake gasket and run it all the way across the end rail and dab it on the other gasket. Try and make the bead at least as thick as the cork gaskets would have been.

5. For coolant sealing, use your finger and apply a thin coat of Permatex Blue RTV around the coolant ports in the intake gasket. Do this only on the intake manifold side of the gaskets, and not on the head side.

6. After allowing the RTV to tack up for a little while, lower the intake manifold onto the gaskets/heads. Torque to spec, following the intake manufacturers or shop manuals torque sequence. Some people prefer to torque in stages or multiple times, and it is recommended to recheck after a couple start ups/cool downs. Be especially careful when torquing/tightening the four corner intake bolts. It is common for people to overtorque here can crack the intake manifold corner ears.

Note: People will argue to the death over RTV vs. cork end rail gaskets, or whether or not to use Permatex Blue RTV on the coolant ports on the gaskets or not. One thing I have come across, is that Fel-Pro, Edelbrock, and Weiand...in all of the instructions I have come across, all say to do as I have outlined above (with the RTV). Between these aftermarket manufacturers and countless engine builders, along with plenty of firsthand experience on my EFI 5.0L and carbureted 289, I'll use the RTV as outlined.

I used to be a believer in the cork gaskets, but have turned to using just the RTV. It makes things easier when you set the intake on and torque it down.

The leak is most likely to be from the end rail at the back of the intake, but it is possible that a valve cover is leaking too. Most likely from the intake though, see if you can pinpoint it. Wipe the oil away and run it for a little bit and see where it starts leaking again.

lol be careful I just tore mine down to fix a simple oil leak and found the head gasket leaking into the valley that holds the push rods. Not alot but enough to take the rest of the car apart and fix it right.

Felpro makes a nice rubber gasket for front and rear intake that has worked very well for me also

If you user RTV don't forget to let it set up a little before putting the intake back on.

Fox8950 said:

Felpro makes a nice rubber gasket for front and rear intake that has worked very well for me also

Click to expand...

+2 Thats what I have used without any problems, they have side rails on the side of the rubber strips to prevent it from sliding in or out, and have little nipples I believe that also hold it in there too. They came in a gasket kit I had gotten.

Don't forget to put some silicone/rtv in the corner of where the intake and heads meet at the end of those rails too.

I put silicone/rtv on both sides of the gasket around the coolant ports I believe. No problems here, how come your not supposed to put it on the head side?

If your gasket kit says you have end seals #95504 and #95505 then its the rubber end seals, just happened to have my intake yanked off and thats the numbers stamped on em
Summit has the kit here don't know if anyone just sells the end seals.
http://store.summitracing.com/partdetail.asp?part=FEL-MS93334&autoview=sku

Garanteed its the rear lifter valley gasket. I had the same problem a week ago. The kid I bought my car from used all RTV silicone and it leaked like a stream! I bought Felpro Part # 93334 from autozone ($10.99) it comes with metal base with rubber intake/head gaskets, and rubber silicone front and rear gaskets. I used a 1/2 circle of RTV at the corners where the rubber end gaskets meet the intake/head gasket and it solved all my problems. I would recommend doing it the same way. HISSIN from the board recommended this gasket yet, and it worked AWESOME! Althought you have to take a dremel if your using any other intake/head combo other than stock, since the ports are smaller.

Hope this helps!

Check the pcv valve grommet also. That was where I had a similar issue once.