I guess I did a pretty ****ty job checking the engine before I bought this jeep last month. I noticed an oil leak on the the passenger side of the engine where the meets the block. There appears to be some oil in the coolant but no coolant in the oil.. I did an engine block test and it didn't detect any exhaust in the cooling. Some oil is above the gasket but I couldn't trace it to the valve cover. I ordered UV oil to make sure this is the leak source. So much for spending $5k on a pre 2000 Cherokee with under 100K miles.

Thanks for letting me rant.




This appears to be the source (below image). There is oil above the head gasket here but the valve cover feels and looks dry.



Small amount of oil. There was a little more but I scraped it with my finger to check its consistency.

 

Compression check all cylinders.
Dealt with similar prob in another motor (chevy)
But my coolant was like coffee w/ half half in it and burning in cylinders during ignition.

If you are gonna do the the gasket or have a shop do it DONT Drive it anymore.
Even driving a few miles is enough to start getting a bad mix in places that dont want it i,e. bearings, rings, lifters, etc.

 

I'll do a compression check Monday. At least I have a good arsenal of tools.

As far as not driving it... It's probably been driven with this issue for a while. It never overheats (though there's a slight bubbling sound in the radiator), and the oil in the coolant is minuscule. It doesn't seem like a major failure. If it becomes a major failure by the time I replace the gasket it's stroker time.

 

If it's not real cold where you are consider cleaning the engine before you add the UV.
Does it look good inside of oil fill cap?
Has oil or collant level been dropping?
That little bit of oil could have been from a dirty funnel.
Might consider an oil analisis.

 

IDK I could be wrong here but I really don't see what's wrong with the first 2 pictures. It's a 4.0. It's old. The engine is going to be oily. Unless you see a constant drip (which will eventually drip onto the ground obviously) - then I wouldn't worry about that area.

As Larry said, if you aren't noticing coolant/oil loss, and the oil in the coolant is really as miniscule as it looks - it's probably barely an issue.

You need a compression check like yesterday. If that turns out ok, and there's not 2 adjacent cylinders that are way low, or something else way out of whack, I'd bet you're fine.

 

Thank's for the replies guys! I knew I should have done a compression test the other week when I replaced the plugs, but I was lazy. I haven't had it long enough to be able to tell if there's any oil or coolant drop. Where the engine and transmission meet is wet from this leak (I thought it was the source until I traced it up to the around the heads). There are a few oil spots where I park it. The engine does make a bubbling sound for several minutes after its turned off (just realized it was coming from the block not the radiator). With the cap off the coolant rises and will pour out in a minute or so but isn't blowing out like you'd expect from exhaust gases (which makes sense because no CO2 was detected).

This weekend I'm in the middle of tearing out the interior and prepping it for bed liner. I'm off Monday (gotta love working for a bank) and will clean up the engine, do a compression test, and put the UV dye in then.

This is a shot inside the oil fill cap. No clue what the white spot is but doesn't look like coolant.

 

Leaky 4.0 looks pretty normal to me.

That looks like a paint spot in your picture.

 

I'm glad to keep hearing that. And yeah it looked like paint to me too.

 

My 96 XJ block looked just like yours. Was leaking oil from under the dizzy. Replaced the gasket, leak gone! That could be your problem. As for the oil in radiator, just keep an eye on to see if it gets worse.

 

2000 with a distributor is unusual, have you checked that the engine block matches the VIN?

 

It's a 99.