When I first start my 94 xj the oil pressure is fine (up at 40) the n as I am driving and it gets warmer it slowly starts to drop to 35 then 30 and when im a at light its only at 5psi! Now I think its either the oil pump, oil screen is clogged or a rod bearing but I don't have any knocks or pings.....can someone help me out??

 

Get a mechanical gauge and test the pressure that way. Electrical gauges can have gremlins, mechanical gauges don't lie.

 

How many miles? And just curious how is the idle speed? Might be with high miles, thin oil, and a low idle .....that is low.

 

200k on new internals

 

x2 on the mechanical gauge

 

Mine is a 2000 with 155k on the clock. At start up it has 40-50 lbs and stays anywhere from 30-40 while under a load. Now when stopped and idling it's at 15-20 lbs. Is that ok? I have though about putting a mechanical gauge on it and run straight 30w oil with a bottle of lucas? What do y'all think I want it to last?

 

Want2wheel, you seem to just have signs of a worn engine. I wouldn't worry until it starts making noises.

 

It rarely freezes here and is nearly always above 50. With high mileage I use 30W and am sure to warm it up a bit when it IS cold. with multy grade my Jeep knocks a little, don't have a gauge. I've never lost an engine runing Castrol 30 W. It's been that way for 10 years. I can here it knock with multy-grade.

 

i run a 15W40 in my rig, but i always let it warm up and i have 216K on the clock. no knock. 45psi that drops to 25-30ish s it warms

 

15w40? Where can you find that I look everywhere but all I see is diesel oil in that weight

 

I'm not sure the lower end even knows weather or not it's in a diesel. Maybe someone here can add....

V thanks Andy
V
V

 

Anyone with a 2000 or 2001, it might be that 0331 telling you its cracked. Check for foam under the oil cap first. I have a 2000 and i put the right oil in and my oil pressure gauge stays in the middle. A different weight oil is just a bandaid or a mental thing, dont fall victim and dont think you know more then the engineers that made it.

 

15-40 is diesel oil. The thing is, diesel oil won't hurt a gas engine. It just has extra cleaners for things like soot.

 

Are you serious? With that thinking we might as well put motor oil in our differential cases lol, How does it know its a differential?

The diesel only came in 2.1 and 2.5 flavors btw. And had no power.

 

Yea the cleaners might not "hurt" the engine but the wrong weight does, slowly but surely. Why does everyone think they know what the long term abuse of the wrong weight oil is. So what if this guy ran 300,000 on diesel oil or vegetable oil or baby oil, he would of ran more with the right oil. If you've got clicks and ticks then maybe bandaid it with thicker oil, but im just tired of these backyard oil chemists.