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Low oil pressure when warm, engine sounds good when cold.

Yoshisakan

NAXJA Forum User
Location
Cleveland, OH
I have done a lot of research recently into the 2000 XJ, and the notoriously bad when overheated 0331 head. That being said, I am looking to buy a clean 2000 XJ with 104k, for $3500.

After driving the truck for a few minutes on the highway, i pull to a stop light. The check engine light starts flashing, oil pressure drops to zero, and check gauges dummy light lights up. Upon driving, I couldnt go faster than 45mph, it would hesitate.

I powered down the truck, turned it back on, and the flashing went away, and I was firing on all cylinders again. When I got back to the dealer, they ran the codes and showed me a random misfire and a cylinder #3 misfire.

I checked the oil, no signs or smells of coolant. Resivoir is a dark muddy brown color. One of the electric fans is starting to fail.

So, at this price, I would be alright with buying an alabama cylinder head, and replacing the entire cooling system, providing that the main and rod bearings havent been damaged by the coolant leaking into the oil pan (If the head is indeed bad)

My question then is, if there was damage to the bottom end, wouldnt the engine sound kind of bad when I start it cold? It motor runs fairly quitely, so I'm hoping this is a combination of a bad oil pressure sender and crank angle sensor.
 
This may be one to skip. A lot wrong at the start. For 3500 it should be fairly sound. The low oil pressure aint going to get better with out new bearings. So figure a complete new engine. So add about 1800 to the cost for a rebuilt.
Ron
 
If it has a Fram filter, swap it out for a different brand and then check the oil pressure.

If you do the bearings, don't forget the cam bearings.
 
This may be one to skip. A lot wrong at the start. For 3500 it should be fairly sound. The low oil pressure aint going to get better with out new bearings. So figure a complete new engine. So add about 1800 to the cost for a rebuilt.
Ron

he didnt buy it for 3500, he is looking for another one for 3500. and if he decides to replace the bearings, its going to be alot cheaper than 1800. he can just pull the motor, flip it, replace the bearings.
 
So bad bearings for sure then? That's a bummer, the body was in pretty good shape. I guess I will hold out for a while and look for another.
I have a project car taking up my garage space, so I cant really afford to pull another motor right now. I was looking to buy this for my daily driver.

I was hoping to find something for no more than $5000, but I'm not having much luck around Cleveland. Would I be better off looking for a grand cherokee, or did they have the same head problems from late 99-2001?
 
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Not sure, I noticed that after I changed all 4 of my jeeps, 3 97's and a 98 using my normal NAPA golds and new Mobil-1 High Mileage API SL my oil pressure at cold is fine, after warm up I get the same drop to -0- on the gauges on both my 98XJ and my 2 97TJ's, they never did this before. The ZJ got my last remaining 5 quart jug of Mobil-1 before the newest SL rated stuff went in and it has been fine. As soon as any of the low pressure ones get it's rpms above 900 the pressure shoots right back to 40+. I'm replacing the sender on the XJ now with one from NAPA vs the one I got a few months ago from AA.
 
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