i believe my rear main seal is leaking. i did a valve cover gasket tightened it up real nice. still seems nice and wet right where the rear seal it. now heres the thing i plan to do the rear main with the oil pan gasket. but while im in there should i replace the oil pump and oil pump screen? shes pushing a good 220k with a bit of a lifter knock. just seeing if theres some experts or experienced cherokee owners out there have an opinion. only a year of owning one and i love it wanna keep her running without having to do a motor swap right now.


also new to the board this place rules!

 

Make sure the leak you're seeing dripping off the back of the engine is not originating at the distributor, oil sender, or oil filter adapter O-rings.

 

You can get an oil pump rebuild kit for it. Good as new for less cash.

 

I have owned my cherokee for 3 years and still havnt replaced the rear main. I did it on my old yota but from what I have read and seen every rear main on the 4.0's leaks... So I havnt bothered. My neighbor has a cherry 89 with a crate motor, everything done professionally. Thing leaks at the rear main...

 

I have a 87 XJ. I just did a rear main and oil pan gasket. I also replaced the oil pump. Mainly because to get my pan off I had to take the pump off then I found the gasket for the pump was only available with a new pump. But I thought about it and who knows if the pump has ever been replaced and for good measure since I had it all apart I decided it was a good idea to replace it.

If you do replace the pump make sure you prime it before starting your engine.

 

I found this:

"The 4.0L was a strong performing engine. There were a couple of issues with the basic design, including leaks; the oil pump was notorious for wearing out at around 145,000 to 155,000 miles, and the TPS (throttle position sensor) on the 1989/1990 models would fail if someone spit on the sidewalk. Make sure you have about 30 lbs oil pressure at idle (+/- 5 lbs)"

citation: http://www.allpar.com/mopar/40.html

 

If some one spits on the side walk. Lol

Also I've noticed the CPS fails if a small child bumps there head on a coffee table. But only in your time zone so it's not too bad.

Ok sorry. Not trying to hijack the thread. Lol

 

[QUOTE=vickin;1418170]I found this:

"The 4.0L was a strong performing engine. There were a couple of issues with the basic design, including leaks; the oil pump was notorious for wearing out at around 145,000 to 155,000 miles, and the TPS (throttle position sensor) on the 1989/1990 models would fail if someone spit on the sidewalk. Make sure you have about 30 lbs oil pressure at idle (+/- 5 lbs)"

Wrong info. Someone isn't informed. 1987 to 1990 had the same finicky TPSs.

Factory spec for idle oil pressure is no less than 13 PSI.