97 XJ low oil pressure......1 millionth thread
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97 XJ low oil pressure......1 millionth thread
Hi all. First time posting. I know there has been a million posts about this issue, trust me I've been all over them for the past couple of weeks, but all of them seem to end with "sending unit." If anyone can help I would greatly appreciate it. Here is the rundown of my situation:
4.0 I6
150,XXX miles
10w-30
Cold start: 40 - 45 psi
Hot idle: 8 - 9 psi
1600 rmp (cruising): 20 psi
Head gasket repaced within the last 1k miles and there does not appear to be any cracks in the head or coolant in the oil.
Shortly after buying the XJ I found that my oil pressure gauge would randomly drop causing the check gauges light to come on, especially while off-road. I checked out the sending unit and saw that there were loose connections on the connector, so I replaced that with a new one from NAPA. When I saw that the pressure was still running low I had a mechanical test done and confirmed that the numbers that I am getting are accurate. After the test I had an oil change done, replaced the oil filter (NOT a fram) and added a bottle of slick 50 but saw no change.
So now that I have ruled out the sending unit, how much trouble am I in? I suspect the issue is warn bearing, but I am not getting any unusual knocking sounds from the engine. At 20 psi how far can I safely drive without doing catastrophic damage?
Again, any assistance would be greatly appreciated.
4.0 I6
150,XXX miles
10w-30
Cold start: 40 - 45 psi
Hot idle: 8 - 9 psi
1600 rmp (cruising): 20 psi
Head gasket repaced within the last 1k miles and there does not appear to be any cracks in the head or coolant in the oil.
Shortly after buying the XJ I found that my oil pressure gauge would randomly drop causing the check gauges light to come on, especially while off-road. I checked out the sending unit and saw that there were loose connections on the connector, so I replaced that with a new one from NAPA. When I saw that the pressure was still running low I had a mechanical test done and confirmed that the numbers that I am getting are accurate. After the test I had an oil change done, replaced the oil filter (NOT a fram) and added a bottle of slick 50 but saw no change.
So now that I have ruled out the sending unit, how much trouble am I in? I suspect the issue is warn bearing, but I am not getting any unusual knocking sounds from the engine. At 20 psi how far can I safely drive without doing catastrophic damage?
Again, any assistance would be greatly appreciated.
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Year: 1999
Model: Cherokee (XJ)
Engine: 4.0L
http://www.jeepforum.com/forum/f19/4...fixed-1304679/
Maybe you'll get the same result.
...the oil gallery behind the sending unit getting clogged with sludge. So I took off the mechanical gauge and left the brass adapter in the hole and stuck a short piece of rubber hose to that and into a drain pan. I then turned it on and revved it at 4000 for about 8 seconds and shut it off. I checked the drain pan and found some obvious bits of sludge that had been blown out. I connected the mech gauge again and topped off the oil. Turned it back on and problem solved! Pressure at idle now 18-20 psi and 60 psi at 2500. Replaced original sender and dash gauge was back to normal...
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My oil pressure went negative, shut it off, waited a few minutes & it went back to normal. As soon as I found a parts store I swapped out the Fram oil filter for a different filter & it never happened again.
Not saying that is your problem, just throwing it out there.
Not saying that is your problem, just throwing it out there.
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#11
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Year: 2004
Model: Grand Cherokee
Engine: 2000 4.0
Cold start: 40 - 45 psi
Hot idle: 8 - 9 psi
1600 rmp (cruising): 20 psi
I suspect the issue is warn bearing, but I am not getting any unusual knocking sounds from the engine. At 20 psi how far can I safely drive without doing catastrophic damage?
Again, any assistance would be greatly appreciated.
- No knocking is a good sign
- The fact you have some pressure means you have oil flowing through engine
- Pressure is not a function of reliability...it is an indicator of wear
- How far and how long your engine will last is a crap shoot
- Don't use slick 50 or heavy oil....it will raise pressure only because it reduces the flow! Flow is what lubricates....do not restrict it with thick sh**.
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High mileage, low oil pressure is nothing unusual. If wear is equally the same throughout engine the accumulative effect will cause low pressure....BUT, and this is interesting: the clearances can still be within the high end of factory specs!!
- No knocking is a good sign
- The fact you have some pressure means you have oil flowing through engine
- Pressure is not a function of reliability...it is an indicator of wear
- How far and how long your engine will last is a crap shoot
- Don't use slick 50 or heavy oil....it will raise pressure only because it reduces the flow! Flow is what lubricates....do not restrict it with thick sh**.
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