head gasket oil leak

i have an oil leak that is from the passenger side were the pushrods go down to the block. there seams to be a leak that is all the way down the left side of my 4.0 now that i know wat the problem is i can easily fix it but i would like to know what caused it. i dont want to do it again since i'll have to get new head bolts and another head gasket if what caused it isnt fixed. my xj has 156ooo miles on as far as i know the original engine. i recently did a tune up and and all point check so all that is lacking is the oil leak.


i have been told that maybe its a bent push-rod but it runs fairly smooth at idle

Before you go to a lot of work, check your PCV system. A blocked tube from the valve cover (common) will cause an increase in crankcase pressure, and force oil out. Its worth a check.

Did you recently put a load of synthetic oil in? I here lots of folks talking about syn oil in old engines leaking in places they never leaked before.

My 89 has seeped from that side since new and I still am only 1/2 quart low at 3,000 miles w. over 150,000 miles on the 4.0 engine so I must not be losing much. The seepage is coming from the push rod galleys on that side. I remember reading on the forum info from a jeep tech that they all did that and eventually jeep redesigned the head gasket to try to prevent the seeping. There is apparantly not enough force on that side of the head to keep the gasket tight due to the design of the head and the bolt locations. If you don't lose much oil it is not worth fixing IMHO. Greg

MCD said:

i have been told that maybe its a bent push-rod but it runs fairly smooth at idle

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If it were a bent pushrod not only would it run rough it would clatter like hell. Worse then a sticky lifter.

Steve

I have a 99 XJ and noticed that the head gasket is leaking at 55,000 miles.It is not enough to worry about I have not even seen any spots on the floor but it looks worse than it is. I never have to add oil between changes. I used to own an 87 and that one leaked all over it just was not worth fixing to me. I do not know what causes the leak because I have a replacement gasket kit just sitting here waiting for me to find time to replace it I 'll post what I find when I am done. Every Jeep I have ever worked on with a four litre seems to be the same way. They are not terrible leaks just enough to make the engine a mess.
Joe

SOOLONG said:

They are not terrible leaks just enough to make the engine a mess.
Joe

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Helps keep the rust at bay for us guys in the 'salt belt' states! :laugh:

Steve

Are you guys talking about head gaskets, or valve cover gaskets?

When head gaskets go, they usually result in loss of compression and/or loss of coolant LOOOOOOOONG before they might result in an oil leak. Although the engine oiling system gets up to 50 or 60 psi, that pressure does not get to the head. The lifters are in the block. Oil is fed to the lifters under pressure, squirts out of the lifters and runs up the pushrods under somewhat reduced pressure, and then drains back out of the head by gravity. The locations where oil goes through the head gasket are not pressurized.

It's more likely that the valve cover gasket as allowing oil to run down the side of the engine. The clogged CCV problem mentioned above can contribute to this.

i have a new valve cover gasket. i think it is the ccv or pcv that is causing it. im gonna blow them out with carb cleaner later and see if that helps.

p.s. how do i tell if tha pcv valve is working, i know its open cuz i get oil in my air filer from the hose.

I have rechecked the gasket several times because I thought it would be the valve cover for sure. But after three checks with oil dye in the system it is deffinetly coming from the head gasket. I would not call it an out right leak it is more of a seapage. I even replaced the valve cover gasket and while doing so checked the torque on the head bolts. I can not belive that the head gasket leaks. The factory gasket is a good quality gasket a 7 layer metal gasket (If I remeber correctly). Oh well I am not happy unless I am working on it any way.

Joe

MCD said:

p.s. how do i tell if tha pcv valve is working, i know its open cuz i get oil in my air filer from the hose.

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Nope. Oil in the air cleaner is how you know it's NOT working.