Oil leak... but where?

At this point I am ready to drive to Colorado and drive my 1996 Jeep Cherokee Sport 4WD Automatic 4.0 off a nice big a** mountain and I don't mean in a nice fun off roading sort of way.


I have replaced many things on my XJ....

I know this is such a horrible question to ask, being that there are SO many possible answers, but I am hoping perhaps someone could give me some insight...
I can tell you that I just changed my oil, filter and not too long ago, the oil pressure switch, so I know it's not the switch. The filter doesn't appear to be leaking at the point of the k&n oil filter being attached to the jeep. Also the cap is tightly secure and no leaks around that point.

I took my son to the park, drove not even 5 minutes to stop and get a Gatorade as it's 101 degrees here today in horrible humid FL, I stop and smoke is coming from under the jeep as I jump out, not a lot just a small enough amount that you go "wtf?!?" I lay under the jeep and see it's dripping onto the pipe and the smoke is it being burned off. Again not by any means "a lot" of smoke, just enough to catch your attention. I let the car idle as I run inside with my son, come back out, put him in the carseat and then back up far enough to be able to see the puddle on the ground, not by any means a "large puddle" but a small puddle, I used a blue rag, to make certain it was in fact oil, and smelled it as well.


Any idea where I'd look first? I could tell when I laid down to look under it that it was dripping off something, what I couldn't tell but it wasn't the oil drain bolt, which is also new.


Could use some help as to know where I should start first and If there is any shortcuts, like how to tell if theres a blown head gasket or anything else, any ways to check for these things would be much appreciated.


Thanks again my fellow Jeep nuts.

--Jessica

Let it cool off, get a good light out and look for the highest point. If it wasn't doing this before the oil change, it is probably something that was moved or changed during the oil change so that is where I would start. Only way to know for sure is to see it.

I had been dealing with a radiator overheating, but that has been fixed (new petcock valve, hoses, drained, flushed and refilled with 50/50 and the radiator stop leak fixed my small pinhole sized leak), so I am now wondering if the radiator leak and this go hand in hand

You sound like me back in March when I bought my cheap but leaky XJ. Don't waste any more time trying to eyeball where the leak is coming from without doing a UV dye test - a cheap and effective solution.

I purchased the following parts from Advance Auto with a coupon code and online order/pick up in store I saved 30% to boot:

AutoCraft UV Leak Detection Kit
Part No. AC992/UVA-1CS

Interdynamics Oil and Fuel Systems UV Dye (1 oz.)
Part No. 374CS

Put that dye in where you normally pour in the oil, drive it around town. Then park in a garage at night with the lights off, or at night outside will do but try to get somewhere with very little ambient light, use the UV light and glasses to see where that oil is coming from. Sure there are better kits out there but this did the trick for me - which was to show me that I had a constant drip from my rear main seal.

Replaced the oil pan gasket and rear main seal, no more burning oil, no more puddles on the driveway :smoker:

Good luck!

I know the XJ is notorious for the rear main seal leaking, how long did it take from start to finish to replace it yourself?

Whats ODD about this is my Jeep hasn't had a drop of oil leak and now all the sudden it's leaking?! Wasn't a drop of oil on the ground before we went to the park.


If i go the route you recommend beasticles, I'd rather open the garage and let it idle after putting in the dye; how long should it let it run for?

beasticles said:

You sound like me back in March when I bought my cheap but leaky XJ. Don't waste any more time trying to eyeball where the leak is coming from without doing a UV dye test - a cheap and effective solution.

I purchased the following parts from Advance Auto with a coupon code and online order/pick up in store I saved 30% to boot:

AutoCraft UV Leak Detection Kit
Part No. AC992/UVA-1CS

Interdynamics Oil and Fuel Systems UV Dye (1 oz.)
Part No. 374CS

Put that dye in where you normally pour in the oil, drive it around town. Then park in a garage at night with the lights off, or at night outside will do but try to get somewhere with very little ambient light, use the UV light and glasses to see where that oil is coming from. Sure there are better kits out there but this did the trick for me - which was to show me that I had a constant drip from my rear main seal.

Replaced the oil pan gasket and rear main seal, no more burning oil, no more puddles on the driveway :smoker:

Good luck!

Click to expand...

Well verify it is that with the dye first - you definitely don't want to have to do that job if it can be avoided. Common leak spots are from the valve cover gasket, the oil filter adapter, the oil pan gasket, and the rear main seal. I ordered those in order of difficulty (I did all four recently on my 2000 XJ). I probably had 10 hours into my rear main seal and oil pan gasket, but I am a total newb (it was my first one) and I was doing it by myself, and I was not in a particular rush. I also ran into an issue with needing brass punches and lost 2 hours trying to remove the upper RMS with the wrong tools.

I personally would just drive it around the block/neighborhood to make sure the engine is nice and hot and has a chance to slosh the oil around a bit. 5-10 minutes at operating temp I would imagine would do it.

Is your engine temperature astronomically high? If so you may have an oil leak around t/ engine. As you drive periodically check your dip stick level making sure your aren't losing oil. Should your oil level remain unchanged then an engine oil leak isn't occurring. The 101* temp. could be causing residual oil to seep from behind t/ flywheel cover eventually ending with time and decreased temps. Cheerio & Regards er uh English?...

Nope, temp is good, fluid levels are good as well, no leaking anywhere I can find just this random out of the blue, hey I feel like annoying the sh*t out of Jessica oil leak today that started randomly, from who knows where.

It's storming like crazy or I'd have already grabbed the dye tester kit, hopefully I can have it figured out by tomorrow

mechbullxj said:

Is your engine temperature astronomically high? If so you may have an oil leak around t/ engine. As you drive periodically check your dip stick level making sure your aren't losing oil. Should your oil level remain unchanged then an engine oil leak isn't occurring. The 101* temp. could be causing residual oil to seep from behind t/ flywheel cover eventually ending with time and decreased temps. Cheerio & Regards er uh English?...

Click to expand...

The issue was, I went in to buy oil... I didn't need a filter as I had an extra new K&N filter, the yahoo guy at Autozone (my autozone is full of kids who can't get a McDonalds order right) said "it's actually cheaper to buy this oil & the filter" I was like "umm ok" so he went off grabbed my filter and came back. I got home and instead of putting on the K&N filter that was inside my house upstairs, I said eh I'll just use this one.... low and behold it was the wrong filter. No kidding, I swapped filters. Issue is resolved.

**Initially I wasn't leaking fluid at all, then I was leaving the park with my son and pulled in to get some gatorade and oil was all over the ground.

Again the issue and all my Jeep issues, THANK GOODNESS, are gone!

I do however have a reading of 60 on my oil pressure switch, but she runs great and doesn't leave a drop of fluid anywhere on my new concrete.

My oil pressure switch/sending unit is new, the filter and oil are new.... what could be the cause of the somewhat high pressure reading at idle?

Thanks!

Edit just seen you solved the problem.



Do a solid degreasing on the motor then after its clean drive it around for 30mins or so. Should be able to find any fresh oil trails drips easier. If it's anywhere near the bottom rear of the motor you got a leaking rear main.

Some xj's also develop leaks around the head gasket that seep over time but that wouldn't likely be close enough to the exhaust to cause a smokey burn off.

I replaced my rear main after work one night wasn't fun but wasn't hard either. Remove oil pan ( get a 1 piece gasket to replace it ) remove rear main use a small punch to spin the upper portion of the seal and use pliers to finish removing it. Replace in opposite order use some rtv around the spots the upper and lower parts meet re torque the main clean old gasket material off reinstall pan using 1 piece gasket. Takes around 2-6 hours longer if you like to your time and be lazy about it like i did.

I wrote this a long while back just for cases like this:




I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.

Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.

Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?

A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.

First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.

Revised 02-26-2013

cruiser54 said:

I wrote this a long while back just for cases like this:




I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.

Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.

Many mechanics, friends, people on Jeep forums who can’t see your Jeep from where they’re at, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?

A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.

First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.

Revised 02-26-2013

Click to expand...

Good advice, all the more reason to buy the cheap dye test rather than shooting in the dark. I found that your guidance was the opposite of my circumstances, I replaced every gasket other than the RMS only to find with a dye test the RMS was leaking. Replaced the RMS and leak is gone. Moral of the story being, it just depends on the vehicle, but a dye test is the easiest way to tell for sure where the leak is coming from.

Combine the dye test with my tips and you can't go wrong!!