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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Alright so after I bought my Cherokee the oil pressure was low and the check gauges light came on. I did some research and found the obvious sending unit is a common problem. I switched that out and now my oil pressure idles at 15psi and when I'm driving is anywhere from 30-50. I'm just curious if that low pressure at idle is ok or if there's something more I need to look into. Oh I ran seafoam through it and just changed the oil today and still getting the same psi... Any thoughts? Or is it ok to continue as is and just monitor?
15 psi is fine. My 99 has been at around 15 psi (at hot idle) since it was new.
The oil pressure spec for your XJ is not less than 13 psi at hot idle and between 37-75 over 1600 rpms.
But as you have a 2000, you must check the coolant level in your coolant reservoir at least weekly. The 00-01 XJs came from the factory with the 0331 cylinder head, which has a known casting defect between cylinders 3-4. Maybe you are already aware of this, but as you mentioned you just bought it, it's worth mentioning. Educate yourself about this. The #1 symptom of a cracked 0331 head is "unexplained coolant loss" and if the head cracks and you don't catch it quickly, it will wipe the bearings and also your oil pressure.
15 psi is fine. My 99 has been at around 15 psi (at hot idle) since it was new.
The oil pressure spec for your XJ is not less than 13 psi at hot idle and between 37-75 over 1600 rpms.
But as you have a 2000, you must check the coolant level in your coolant reservoir at least weekly. The 00-01 XJs came from the factory with the 0331 cylinder head, which has a known casting defect between cylinders 3-4. Maybe you are already aware of this, but as you mentioned you just bought it, it's worth mentioning. Educate yourself about this. The #1 symptom of a cracked 0331 head is "unexplained coolant loss" and if the head cracks and you don't catch it quickly, it will wipe the bearings and also your oil pressure.
Enjoy your XJ!
Yes. Own an '00 myself. Always keep a close eye on the coolant. I do not have any of the symptoms associated with a cracked head. Chocolate milk looking oil or crud under my valve cover or on my oil filler cap. No unexplained loss of anti-freeze. Little or no oil pressure at a very hot idle. My gauge read about 22lbs at a very hot idle.
Well I didn't think to much about it but when I changed my oil but it was a milky brown color and some crap on the filler cap. I thought it was just the seafoam. Now I'm nervous I have replace the head because I do have a slow what I think to be unexplained coolant loss cause I can't seem to find any leaks. Did find what looked to be coolant under a hose connection. Tightened the clamp just haven't really driven it to see if there's any loss yet.
Well I didn't think to much about it but when I changed my oil but it was a milky brown color and some crap on the filler cap. I thought it was just the seafoam. Now I'm nervous I have replace the head because I do have a slow what I think to be unexplained coolant loss cause I can't seem to find any leaks. Did find what looked to be coolant under a hose connection. Tightened the clamp just haven't really driven it to see if there's any loss yet.
Do not want to scare you so we are going to tread lightly. But. What does the odometer say? 111K? Got about 154K on mine. For all I know the head was replace by one of the PO's. I am the third owner and have had it coming up on 3 years now. What does the gauge read at a real hot idle? I don't mean when getting her up to temp. I mean after a good long highway type blast.
Usually driving it for about an hour 30 min down 30 min up.. The temp usually reads right around where the picture is.. 210 give or take. And yes the odometer is 111xxx
18 lbs at a really hot idle. That is pretty good. They way people seem to explain about the cracked head is about 5 lbs or less at very hot idle. Here is a picture, Google is a beautiful thing, of what the crap looks like indicating water in oil.
Well this is just a picture off the internet. So we have to take it for what it's worth. Like tjwalker said they are prone to cracking between cylinder 3 and 4. What happens, according to what you read on the internet, is that as the Jeep gets hotter the crack widens and this is where the anti-freeze loss and low oil pressure come into play. Wish I could be more helpful determining where you are at. There is always the possiblilty you do not have this problem or maybe it is just a blown head gasket. There are probably ways to more properly diagnose a cracked head problem with the head still on the Jeep but I am not familiar with any. I know a machine shop can check a head with it off the engine. Thing is you go through all that trouble might as well just replace the damn thing anyway. Just remain calm. Maybe do a little research. Know any real mechanics that you trust? While it sucks not the end of the world.
Unfortunately I just moved to the Denver area so I don't have a mechanic per say but I have a a buddy or 2 that know a thing or 2. I'll call them and get them over here. I appreciate your help!
02-12-2016, 07:09 PM
Low oil pressure
