Gina

Hello everyone. Let me start my post with a big "thank you". This place is a wealth of information; my quest for the exact location of my oil leak began here and many questions were answered through that research. This is my first Jeep; I know enough to be dangerous and am ridiculously stubborn and frugal.

I recently purchased a 1990 Jeep Cherokee Laredo. 187K, leaking a small amount of oil. The owner was a mechanic (I am now questioning his abilities), and replaced the rear main seal. It continued to leak - landing on the exhaust and creating plenty of smoke. I discovered that two of the bolts on the rear of the valve cover were loose (fun to get to!), tightened them, but is still leaking a bit sending smoke into the vehicle. Oil leak is somewhere on the passenger side, but I don't think it's the oil filter fitting.

I replaced the sending unit, air filter and oil filter, but am now reading only 20 on the gauge at highway speed. I also broke one of the plastic tubes going to the valve cover from the air filter. Fixed that with a bit of hundred mile and hour tape. I just started it this morning, and the gauge read 40.... sigh. Definitely running rich - not leaking right now, but idling very rough. Looks like I traded one problem for another.

Starts great, but seems to be dragging and running a little rich. Of course now the transmission feels like it's slipping on the downshift (a different problem entirely, I assume and one far beyond my abilities) Any suggestions?

addendum - oil in the new air filter - searching this now

jsport

well first off if you have oil in your new filter that is no t a good thing at all that mean you have buy pass witch means the rings on the pistons are warn down and is letting oil get buy and going places it shouldent be going that mite be the reson you have leaks

CodeXJ

Not necessarily. He mentioned he broke one of the plastic lines running from the valve cover. I'm guessing the back one? That's the vacuum feed for the crankcase ventilation valve. If this is leaking/broke/clogged you'll get a lot of oil into your air filter. I'd suggest replacing this line ASAP and seeing if it helps.

As for the oil leak, if the two rear bolts on the valve cover were loose, it's probably a bad gasket. Once they separate they don't really compress correctly again. Easy to change

The oil pressure issue is a bit of a concern. Does it sound like the pressure is that low? I'd recommend getting a mechanical pressure tester and testing the pressure that way. If it reports good that way, then your sender is bad. You may also try just cleaning the contacts on the oil pressure sender. It's the unit with the wires running out of it right next to the oil filter.

As for the transmission slipping, if you don't know when it was last done, get the fluid and filter changed in it. When the fluid goes bad it can lead to slipping.

Gina

thanks for the feedback. The oil leaks no more, but now it runs horribly. Before it leaked, but ran well. It doesn't stall, but idles roughly and runs rich. "She" broke the front one, not the rear one - that one came out perfectly. It was clogged a little and I cleaned that one out. My intention for the front one was to bypass those brittle hoses all together and run heater hose from the fitting on the valve cover to the air cleaner. That was until I removed the fitting from the valve cover and it came apart in my hands. This is really getting fun... I rigged a hose into the valve cover, but it still runs rough. Still working on a McGuyver fix for a fitting for the valve cover so I can get to the parts store. I'm thinking that wasn't my problem to begin with.

Starting cold, the gauge runs 40+, but once it warms up, it won't get over 23 or so...

99KeeSport

EDIT: Oops, looks like you fixed the leak. But here is what I posted anyway:

I would change the oil and put in some 15-40w oil with some lucas stabilizer.

Also:

Dyes RULE for finding leaks. Dump 2 bottles in the oil spout, run the engine for about 5 minutes, then use a black light to find the leaks. All your leaks will show a fluorescent greenish color. (The dye is fluorescent orange but when it mixes with the oil it turns greenish). I found four leaks yesterday. My leaks are: rear of oil pan, oil filter adapter, rear of valve cover, and oil sending unit (all famous 4.0L leaks).

The dye doesn't impact the utility of any fluid. Can be used in oil, tranny fluid, power steering, etc.

You can get the dye and black light on Amazon.

CodeXJ

Ooops, my bad. I suspected you were a 'She' but it's hard to tell on the internet.

Is the smoking fixed? You mentioned the leak was, which is good.

As for the oil pressure, at idle when cold you should be 40+. At idle once it warms up you should be around 25psi. As long as you are achieving this, you should be OK. I can't remember what mine runs at, hot, on the highway. Sorry. I've heard that factor spec is 10psi for every 1k RPM.

Gina

Thanks again - I love the dye test info! When I say I fixed the leak, I really mean it leaks much less. I am delaying the inevitable, which is pulling the valve cover, replacing the seal, and cleaning out the ick. I just changed the spark plugs, and have realized it's a mess in there....

Thanks also for the info about the oil pressure. I thought I was supposed to have 40+ at highway speeds, so I guess I'm doing ok; at least there.

The annoying part now is that is still runs like it's being choked - really rich and low, chunky idle. It's got an appointment this week with someone who really knows what they're doing. I know enough to get myself in trouble.

Funny story - bought a muffler the other day, great price; direct fit. Thought it would just come apart like tinkertoys.... It's still sitting on the back seat. Live and learn.