On Dec 17, 4:23 pm, DaveBWilli...@gmail.com wrote:

I would not buy this vehicle, seller has replaced items that would
logically fix a "easy" oil pressure problem, Sounds like when the oil
heats up and thins out some its just not holding pressure, probably due
to excessive wear (and thus too much clearance) on the crankshaft
bearings.

S

Warm the engine up, disconnect the sending unit and put a real pressure
gauge on there.  Start it up and read a real number off a calibrated
gauge and compare it with the one in the manual.

It's possible for an engine with poor oil flow to keep running without
immediate failure but register very low on the gauge.   If this is the
case, you probably don't want to buy this vehicle.
--scott

4. Could the drainback holes in the heads be so plugged that all the oil is
   staying in the top of the engine, and not draining back into the crankcase?

When the gauge goes to zero, what does the dipstick show (running or not)?

I would not buy a car that had low oil pressure.  It is possible that an
engine failure is eminent.  Check the oil temperature if you can and verify
that the pressure sensor is working correctly.

Great deal -first red flag!

Run away run away!!!!

Even if the seller screws a mechanical guage in there and proves that the
engine is maintaining good oil pressure and that the dashboard guage
is broken, once you buy it and start driving it, how do you propose
that your going to know the difference between a "normal" oil guage
reading of zero, and a sudden mechanical problem that would produce
a guage reading of zero?

Oh that's a great one.  Then over the weekend it seizes and you find
yourself in court with the seller telling the judge "it worked fine when
I loaned it to him"

The seller is just trying to emotionally snare you so you allow your
logic to go out the window.  Hell, if your even contemplating touching
this, the seller already has you hooked and knows it, and is just
working on reeling you in.

If you can pick it up for $300 and you have a crashed Jeep
with a perfectly good engine, you might have something.

Otherwise your just going to join the long lines of people who
have too much invested in their car to cut their losses and run,
so they just keep paying and paying and paying...

Ted

Dave, I had a similar problem with a 97 Chev Cavalier (120k miles) I
recently bought.
Engine sounded great and ran great before and after I bought it, but
shortly after I bought the car, the oil light started coming on (will
do when less than 5psi pressure), only after the engine (and oil) was
warmed up.  Took it to a mechanic.  Turns out it had a new oil pump and
head.  Mechanic found scored bearings in the cam and crank.. said worn
bearings and metal dust inside engine.  said the worn bearings were
what was dropping my oil pressure, and advised that the engine would
eventually throw a rod.  (prev owner was a woman...).  mechanic
suspected that prev driver neglected car, resulting in blown head...and
prev repair shop must have replaced oil pump and head in order to patch
the problem.

Strait 30 nor 20/50 weight oil did not fix the problem, but strait 50
weight did... but that stuff is really too thick for a 4cyl.

So I ended up replacing the engine, after so many shops refused to
replace the cam and crank.

you can get a mechanical oil pressure gauge for around $20 at pep boys
and/or O'Reilly auto parts.

so my advise to you is invest in one of those oil pressure gagues, buy
the Hayes manual for the oil pressure specs, and take the car home and
test it (after engine is warmed up)... otherwise, avoid purchasing that
Cherokee.

Tim Sell
North Texas.

The dash gauges are known to be faulty.  A real mechanical test is
called for.

I believe I have even participated in the discussion and testing of the
vehicle you are thinking of buying or someone else has done the same
things we recently talked about on another forum.

That engine was running perfectly while showing no oil pressure and the
owner was getting suckered into more work when everyone on the forum
insisted he get the mechanical gauge test.  He finally did and the dash
gauge was ruled faulty.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos:  Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)

Put a MECHANICAL gauge on it. They're cheap and available at any parts
store- don't bother with a permanent installation, just put the
capillary tube in where the sending unit goes and tape/velcro/whatever
the gauge down while you run the engine. Electric gauges are next to
worthless for real troubleshooting, because 9 times out of 10 the
problem is the gauge itself.