Oil Leak Around Head, Small Puddle on Engine

Hi there. I have a great deal of experience with doing "routine" repairs and other repairs outside of the engine. I have not ventured into removing the head yet, but I am confident I could do so if the need presented itself.

That being said, I have a 1995 Jeep Grand Cherokee Laredo, 4WD. I purchased this vehicle back in 2002 with about 85k on it. Shortly thereafter, I noticed that a puddle of oil that would accumulate on top of the engine, just below the head (in the lower right as viewed from the front of the vehicle). I sopped up the oil with a paper towel, and have continued to do so every 2-3 weeks when I check fluids. The amount would probably be enough to fill up a small aspirin bottle.

I had written this off as a problem from age; this is the newest car I have owned so I was used to old beaters that leaked oil everywhere. When I purchased the car, the dealer told me that the head gasket had been replaced since the old one was leaking and was cork (not recommended by OEM). Vehicle now has 112k miles, mostly highway.

Lately I have been having a problem during long highway driving (2+ hours) where the overdrive locks out and the tranny stays put in 3rd gear. I know this is a "safe" mode for this transmission, so I looked at possible causes. Every time this occured the engine was approaching 210 degrees F and was on a hot day.

I know a symptom of head gasket failure is an overheated vehicle. I'm wondering if the hot engine temp caused the overdrive problem.

I have never noticed any bubbles in the coolant resevoir or seen any leaking coolant. I don't notice any water in oil--dipstick very clean. The exhaust isn't smokey, and I never notice any steam--however when I do put my hand outside of the tailpipe, the exhaust does feel moist (which I think is probably normal).

My question is this. I would be willing to fix the problem if it is necessary. However, given the age of the car is this oil leak just a problem with age? I maintain the vehicle very well, but I don't want to do all of the work of replacing a head gasket if it isn't necessary...say from age of the car, there being a warped deck, etc. Is this oil puddle from a leaking head gasket? If so, is it worth it to repair given the age of the car? I have no other driveability issues, rough idle, etc.

If this isn't a significant problem, then I would like to know so I can move on to other possible causes of this overdrive issue.

If the dealer did actually change the head gasket, I'm wondering if it would just always leak even if I repaired it. Althrough, there is the possibility that they lied to me about that.

Thanks in advance!

Any thoughts on this?

I'd have to look at my 4.0 tonight to be sure I know where the oil is accumulating, but I don't think you have a bad head gasket from what you describe. I think the leak is most likely coming from the valve cover gasket (the only one on the top end that might have been cork). The valve cover is the long upside-down pan that sits on top of the engine. Try tightening the bolts that hold it down a bit to see if you can stop the leak. They don't need a lot of torque, about what you can do one-handed with a 3/8" ratchet.

Thanks for the response Sport45. I will take a look at it later. I was under the impression that the valve cover gasket was the head gasket. But, after looking more closely at a diagram of the engine...the valves would have to be removed to get to the head. I shouldn't have to drain the oil if I were to remove the valve cover, correct? Thanks!

I was told I had a bad head gasket on my old 4.0 cherokee, and I took it in to a reputable shop, and they said the if you have a blown head gasket on a 4.0 they won't leak oil, but coolant. The reason is this. Given that the 4.0 isn't an overhead cam engine, there isn't any pressurized oil going up through the head to lubricate the cam. But 4.0s have a common problem with valve cover leakage, and they have since AMC started using the basic motor in the 70s.

My old '98 cherokee with a 4.0 always ran around 210 degrees, as a matter of fact, I believe these engines have a 206 degree thermostat, so I don't think that you gauge being up around 210 is a big deal at all.

I can't give you any help regarding the tranny overheating though, as I don't have much experience with the 45RFE tranny.

Sounds like good info. I am about to go check the bolts and torque them to spec...I'll let you guys know how it turns out.

I have researched the engine temps in the factory service manual. 210 degrees is normal for the engine, however it is not normal for MY engine. I have never noticed it getting over 210, which it had been when I was driving those long distances under load (i.e., ac on, highway, hot temp, hills)....it got over 210 and continued to climb. I had never seen that before (I always make a habit of periodically checking my gauges while driving). In fact, at one point when the engine was right at 210 I pulled over and checked out the engine....it was HOT....it felt really hot...much hotter than the engine compartment usually gets while driving. At this point, I also noticed that the power steering pump spewed some fluid (I'm guessing there is a pressure overflow on the cap).

The heat hasn't been a problem lately, since I changed the oil the other day (at 3,000 miles). It really needed it too....the oil was BLACK and had the consistency of water.

Again, thanks for the advice. I have always been struggling as a beginning car mechanic...I just found this site and it's a great place to get some pointers.

I checked all of the bolts...they were torqued down per manufacturer's specs. There is definitely oil leaking from underneath the valve cover straight back above all of the cylinders. I am guessing that it is the gasket. Can you buy a gasket for this, or should I make an RTV gasket? Would it be better to use RTV to account for any warpage in the cylinder deck, since this is an older engine?

Thanks!

The gaskets are a rubberized gasket, of which they say you shouldn't use silicone to seal it up.

These never stay sealed completely, I'd be surprised to hear of anyone with a 4.0L with any miles on it whose valve cover gasket wasn't leaking. You can put a new one on, but it will start leaking again, the question is to what degree. Before I got rid of my cherokee, it had around 112,000 on it and it had a slight leak, but nothing as bad as yours.

On these engines, the warpage is typicaly in the valve cover gasket, not in the head. As a matter of fact, the fix from Jeep was just to get a new valve cover.

If you're just getting into this, I'd recommend alldatadiy.com. It costs $25.00 for the first year, but it picked up where my Haynes manual left off.

Good luck on this one.

I replaced the valve cover gasket back in late winter. No leaks yet, but I'm also sure that it will eventually do it again. The leak wasn't much but I went on ahead and replaced it. I've heard it's common with age. My engine is running at 180K miles now.

Also I recently replace my thermostat and hoses. I went with a NAPA version that he said opens up either at 185 or 195. Can't remember due to all these gray hairs getting in the way. And obviously from the gauge when driven the needle doesn't climb quite as high as its done for the past few years.

Another note about the heating. I've got a tranny cooler. I'm no expert but I guess not having to cool the engine and the tranny from one source ought to be good. Having the tranny cooler I feel like has helped mine run as long as it has, along with flushing and changing the filter periodically. Consider adding a cooler. But check with the experts here for advice in case there's something I don't know, which is usually a lot.

i have a 1995 jeep cherokee 4.0 engine that has a small oil leak round the oil filter...my guess that its not the filter...anyone with any ideas i'll appreciate them...thanx

Yeah this is probably the gasket behind the oil filter connector (not the actual gasket that comes with the new oil filter). I had to fix this on mine, too...it was a $3 gasket from the dealer.