NoColoradoGT

Hey guys. Okay. I need helping badly.

My '90 is leaking oil like crazy and burning through about 1 quart every 40 or so miles.

Also, I just did a nice cleaning job on the bay and now there is burnt oil splattered all over the left hand side of the block and the left hand side of the bay. I can get pictures later, I'm just at work right now. I'll try and snap some at lunch.

In any event. I know what all this stuff usually means but I need help figuring out which it is.

I know it could be either a bad valve, bad seals or a head gasket (please God, no. hahah) It's not throwing blue smoke that I can see (the lady has been driving it while i've been away the last three days and had to add three quarts of oil), however it started burning oil so bad last night that it was very lightly smoking from underneath the hood. I had to add two more last night and the dipstick is reading 'Full', however the pressure gauge is lower than 20 psi at all times and drops down to nearly zero at a light.

What in God's name is going on?

tjwalker

With that low of oil pressure, you should also verify it with a MECHANICAL pressure gauge. Many big box parts stores will rent you one of these. Oil pressure spec is as follows:

*Not less than 13 psi at HOT idle
*Between 37-75 psi over 1600 rpms

The suspect for oil leaking on the top end is the valve cover gasket. Easy fix to replace.

For the oil "burning", you must perform some testing to determine the root cause. And the test that means the most here is the compression test. Test all 6 cylinders with a good gauge. Do a dry test, then a wet test with a little bit of oil down each cylinder. SEARCH if you want to learn more about this.

The compression spec for the Jeep 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.

How many miles on this engine? May be getting tired........

Good luck!

NoColoradoGT

Thank you very much!

Yeah, a compression test is certainly needed here.

She's got 150,026 as of last night. However, I would equate the mileage to being closer to 200k because she was severely mistreated by the former two owners. We're talking not changing the oil for a year or so at a time....

How about the oil leaking on the bottom end? Any ideas there? I haven't had a chance to throw her on jackstands yet to see whats up. I've been dealing with this for about 12 hours now since I got back into Colorado late last night.

NoColoradoGT

Update, oil pressure reads 40 psi while the Jeep is off, however drops down to 20ish once she's started.


I need honest opinions...

Do I try to repair this? Or do I cut my losses, try and sell mine for like $1,800 and attempt to buy something like this (I say attempt because if I can't get out the door for $4,000 on something it won't work).

http://www.cars.com/go/search/detail...5&aff=national

I've put a ton of work into this thing and I don't want to sell it if I don't have to. I mean crap, I just finished a 200 hour paint job on it. But I'm honestly not terribly concerned about losing the paint job. It was just 80 bucks worth of rustoleum primer, gloss black enamel, and clear coat, but it was a ****-ton of sanding/wetsanding and I just filled a bunch of holes in the body. I also just replaced the starter on the motor as well as a new air filter, fresh tranny flush, four BRAND NEW tires with less than 300 miles on them, two new U-Joints, about 50 hours of work to get everything on the 4x4 System going good again...and too much more to list.

If y'all didn't see my build thread, here's a quick couple photos to show the transition:





Like I said, I don't want to sell it...but I can see this getting really expensive really fast.

tjwalker

Get some verified test data (compression and oil pressure) before deciding.

Good data = Good decisions.

If you like the vehicle, remember that an engine is simply a "component". A large one albeit, but a component, and swapping in a different one or a rebuilt isn't particularly difficult.

freegdr

are both pollution hoses still connected frfom the top of the valve cover and clear and working correctly