So, I've pinpointed the worst leak on my wife's Cherokee's engine to the oil pressure sending unit.

It was obviously malfunctioning, as it read "pegged" the entire time, but I felt I had more pressing issues, so put it off. When I started to fool with it, I noticed that the electrical plug was full of oil, and that it was wicking down the off side, and running along the oil pan flange, at a rapid rate.

So, off to the J/Y, and would you believe, out of the 12 or so mid-90s Cherokees I looked at, only 1 wasn't leaking through the electrical plug.

When examining the pre-mid-90s oil pressure sender, which isn't a huge cheap-*ssed plastic POS, I noticed that NONE of them were broken.

Seems that putting a cheap piece of garbage right in the way of the oil filter, held together with a flipping o-ring (!!!!!!!) and which fairly invites a ham-fisted mechanic to torque on the plastic sender body, results in cracked and broken sender units. And the local parts stores don't stock it; it needs to be "special ordered".

Provided that you can pump out the contents of your oil pan in a New York minute through this cheap piece of crap, it would behoove Cherokee owners to keep an eye on it.

I would think you could retro-convert the older and bullet-proof unit, just for safety sake. Next time, that's what I'll try.

 

I had a problem with my 93 leaking too. $25 quick replacement after I finally found out what was causeing the drip underneath.

 

I have the older type with half and half, plastic and metal. Mine came from the stealership b/c I needed it in a hurry and the good ones from NAPA were a 3 day wait. Pull it off and slap a real oil pressure gauge in the hole while you wait for a metal one to be ordered. Thats what I would do.

 

I plan on taking off an early, all metal unit (which is about 1/4 the size of the plastic POS) and installing it to see how closely it tracks the older unit. If so, that's a fix.

The local J/Y charged me $5 for a half-plastic/half-metal one, and it works dandy, but it's designed to break. Seems like if the older, all metal ones work, and there's a ton of them at the J/Y, that would be the "right answer".

In the meantime, I bought a special oil filter wrench that doesn't impinge the sender unit, to prevent breakage.

 

Keep us informed as to what you find out, I still have a small leak and I think it's coming from the sender. Hard to tell, though, since the valve cover leaked for years... the engine is caked.

Safe to take it to the local self-serve auto-wash and hose it down?

 

I usually do if I'm gonna work on the engine. I put a plastic bag over the distributor and the air cleaner and soak it in Gunk Engine Brite and then go have a soda and snack. When I come back I use the car wash hose to pressure wash it. NO SOAP JUST WATER.

 

omg same thing happened to me i cant believe i didnt find this thread i searched everywhere for the same problem