oil leak

[Sick6]

Oil leak coming from rear top of engine. The drain hole for the head drains to the lifter valley, correct? I'm thinking it might be running across the cometic head gasket and down the back of the block...

 

[chrisgarrett]

It is most likely the rear of the intake. Sqeeze your hand back there just behind the intake. It's probably wet. Die you use the rubber seals or sealant? Seems like most guys will tell you to use rtv rather than the rubber seals. The one time I used sealant, it leaked like hell. The other times I used the rubber seals and I never had a leak.

 

[slipstick]

I also built my motor with Cometics head gaskets and have an oil leak like you describe. I have tried to determine that the leak is coming from the intake/block seal but I truly feel the leak is through the head gaskets (both sides). Each time I discuss this issue, the response I get is that the leak must be between the intake and block. I have a car lift and have spent much time observing the leak area and each time I conclude that the leak is between the heads and block (head gasket). Lets be sure to post if we ever confirm this leak area.

 

[chrisgarrett]

It is unlikely that the heads would leak oil. It is very possible that the intake would leak oil. Why don't you clean it all up, and put uv dye in the oil. Then run the car and you will see where it comes from. I have used uv in the past and it helped me find a leak that I spent two weeks looking for (front cover). Or put your hand behind the intake, directly under the coil and see if the center of the engine is wet with oil. If it is on top of the engine, it is most likely the intake. When you look up at the engine from below, it looks like the heads are leaking because the oil flows over them as it leaks down from the intake.
Don't mean to be argumentative; just trying to help.

 

[mikestertwo]

It is possible for the oil to be coming from between the head and the block. I have seen this on a couple if motors that other people have built. When the head is torqued down, you get some distortion up towards the top ends of the heads and you don't have the same clamping force towards the top where the oil drain back hole is. My son had this problem on his GN and I showed him an old trick that GM uses. You put a thin layer of that white pipe joint compound on the top and bottom surfaces of the ears on the head gasket when assembling. The leak went away. I do this to all of my engines.

Oil leak coming from rear top of engine. The drain hole for the head drains to the lifter valley, correct? I'm thinking it might be running across the cometic head gasket and down the back of the block...

 

[chrisgarrett]

It seems to me that if you have oil leaking out from under the heads, you have a much bigger problem looming on the horizon. Think of the compression loss and what is happening to the gasket. The oil will soon begin blowing out rather than merely leaking out.
The oil that is fed up to the heads through the pushrods drains directly down back into the valley. How would it make it's way back up to the head gasket?

 

[mikestertwo]

The gasket doesn't leak aroung the cylinder or water jackets. The head bolts are evenly spaced and close enough to prevent that under normal conditions. The problem is the head distorts as you get further from the head bolts. This reduces the clamping force at the upper corners because of the longer distance. The oil migrates down the back of the head where the drain holes are and seeps through the gasket plus you get some positive crankcase pressure on occassion which we are all familliar with these turbo cars which makes the problem worse.

Oil leak coming from rear top of engine. The drain hole for the head drains to the lifter valley, correct? I'm thinking it might be running across the cometic head gasket and down the back of the block...

 

[oddfire6]

i have also seen a head gasket leak oil.

 

[slipstick]

Chris
I have felt (and stuffed white paper towels) under the coil/module and have not found oil dampness. I totally understand how unusual it is that the leak I'm experiencing is coming from the head gaskets. However, at this point in time my observations lead me to the conclusion that the leak is there (head gaskets). I have approx. the same leakage on both sides. I would try uv light if I could see the back of my intake. As it is, the oil appears high on the back side (oil drain to valley area) of the heads and flows down the head gasket to the block and on the floor.

 

[Pronto]

Try the dye. I found a weird coolant leak on my old T/A with it. You'll be able to see for sure where it's leaking. Let us know when you find it.

 

[chrisgarrett]

Okay, let me just play the devil's advocate here. First of all, you understand that I'm hoping for your sake it is just the intake. But all that aside, what are the chances that both head gaskets would leak?
When my intake was leaking, the oil ran down both sides and dampened the juncture where the heads and block meet. I even had my trans guy look up there and remark that he had never seen heads leak oil. Turns out it was not the heads.
I'm not trying to be argumentative or a know-it-all. I'm just saying to make sure it is not the intake before you pull those heads off.

 

[Sick6]

I took the coil pack off my car tonight and found a void in the intake-head-block juncture... I stuck a tube of rtv in there and went to town... The valley in the center of the block was not wet, but any leak out of the point which i describe is on the other side of upper trans bolt, it would flow down the block. Keep in mind that this is a hefty leak that only occured after driving the car... a drip every 2 seconds or so. Test drive tomorrow night, I'll like you know how I make out.

 

[3TURBOS]

The cometics can leak as described. I have had the intake leak and always make sure I will not have it again. Both sides leak equally (oil only-no water). I have a lift and have added oil dye and have not confirmed a leak anywhere else. There seem to be a lot of people that deny a problem exists if they have not seen it first hand. These were put on dry on the stand when no one was recommending any type of spray sealer on the gaskets. The spray may have prevented the problem. A smoother finish on the block and head may have solved this problem also.

 

[Sick6]

f*ck cometic head gaskets. thats all I have to say.

 

[Sick6]

what head gaskets should I use?

 

[chrisgarrett]

what head gaskets should I use?

Felpro 96033.

 

[TurboTnZ06]

Yeah, my pass side cometic leaks at the back. the front half of the head gasket is dry. The intake gasket area is bone dry. The driver side is dry as a bone. F'n engine....