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  #16  
Old June 10th, 2020, 09:39
Black1990jeep Black1990jeep is offline
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Re: Oil Pressure Acting Weird

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Originally Posted by devildog0 View Post
10w30 is not a problem.

Sent from my SM-G892A using Tapatalk

I run 10w 30, recommended for my XJ for normal temperatures. Stay within makers recommendations. now if you have a really worn motor with low pressure a thicker oil may make sense as a band aid to maintain pressure for a little longer, but that motor wohld be on its last legs.

you need to test the pressure with a known good gage FIRST before changing anything.
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  #17  
Old November 18th, 2020, 11:45
Redsnake Redsnake is offline
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Re: Oil Pressure Acting Weird

Did the OP ever figure out what was the issue? I'm going to pick up a mechanical gauge tonight myself to see if my Sensor is bad on my '01 XJ where the Oil Pressures just started dropping to near 0 at hot idle... just wanted to verify the actual pressure before diving in deeper.
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  #18  
Old November 18th, 2020, 12:04
Unclewolverine Unclewolverine is offline
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Re: Oil Pressure Acting Weird

On an 01 there is a good chance the head is/was cracked and washed out the cam bearings, thats what happened on mine. If it is truly 0 at idle there isn't much you can do at that point. Not even new rod and main bearings and high flow pump will help.
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  #19  
Old November 18th, 2020, 12:22
Redsnake Redsnake is offline
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Re: Oil Pressure Acting Weird

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Originally Posted by Unclewolverine View Post
On an 01 there is a good chance the head is/was cracked and washed out the cam bearings, thats what happened on mine. If it is truly 0 at idle there isn't much you can do at that point. Not even new rod and main bearings and high flow pump will help.
My '01 had the 0331 Cylinder head crack ~ 70K miles back. Has been replaced but the bottom end was not rebuilt. Chances are my bearings are finally toast, but at this point the Oil pressure starts fine ~ 45 then drops to nearly 0 when the XJ warms up at idle. Going to hook up a mechanical gauge to it to verify if the Sender went bad or if I'm due for a new engine. Ugh... hopefully it's just the sender, but I shall see. Funny thing is she still runs like a TOP and there is no Engine noise (Knock or Marbles type) noise since the oil pressure went to 0 yesterday. Drove it home from work last night and into work today... hopefully it still gets me home if the bearings are shot. Ha. (knock on wood)
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  #20  
Old November 18th, 2020, 12:40
Unclewolverine Unclewolverine is offline
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Re: Oil Pressure Acting Weird

The factory gauges are notoriously inaccurate thats why I have a manual one mounted in dash. They rarely read the same even though they are teed off the same port.
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  #21  
Old November 18th, 2020, 12:41
Redsnake Redsnake is offline
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Re: Oil Pressure Acting Weird

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Originally Posted by Unclewolverine View Post
The factory gauges are notoriously inaccurate thats why I have a manual one mounted in dash. They rarely read the same even though they are teed off the same port.
Here's hoping it's just the faulty gauge or sender.... and not the bearings.
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  #22  
Old November 18th, 2020, 18:40
hackattack182 hackattack182 is offline
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Re: Oil Pressure Acting Weird

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Originally Posted by Redsnake View Post
Here's hoping it's just the faulty gauge or sender.... and not the bearings.
I'm kind of going through something similar, so curious what you find with the mechanical gauge
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  #23  
Old November 19th, 2020, 16:03
Redsnake Redsnake is offline
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Re: Oil Pressure Acting Weird

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Originally Posted by hackattack182 View Post
I'm kind of going through something similar, so curious what you find with the mechanical gauge
Picked up a set of mechanical gauges at the Chinese tools shop... Maddux brand w/all the bits and pieces needed. Hooked them up and it was reading a solid 15 psi right after I removed my Oil Pressure Sensor that was showing ~ 9 psi on my dash gauge. Revving the engine up to ~ 2000 rpms and the gauge shows near 50 psi. Let the jeep sit and idle for ~ 10-15 minutes while hooked to the Manual gauge, revving and letting idle, revving and idling... trying to simulate driving.

Pressures never dropped below 12-13 psi on the mechanical gauge. So I changed out the Sensor w/a new one from Rockauto, Vemo brand. Hopefully that's a good one. Couldn't find an actual Mopar branded sensor... so we'll see. New Vemo gauge is showing ~ 11-12 psi on the dash gauge. So it's close... and now we'll see how it goes.

I'm also running Rotella T6 5W-40W so I may go up a bit in Viscosity and see if that helps. It doesn't get Super cold here in Tulsa OK... so I may just let my XJ warm up a bit more in the AM during the Winter months... but I think I'm good to keep driving her for a while. Good to know the Mechanical gauge readings now.
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  #24  
Old November 19th, 2020, 18:53
Unclewolverine Unclewolverine is offline
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Re: Oil Pressure Acting Weird

Its low but it is the mighty 4.0; for the most part if it stll has oil pressure it will keep going indefinitely. Might throw a quart of Lucas in there every oil change.
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  #25  
Old November 19th, 2020, 19:02
Redsnake Redsnake is offline
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Re: Oil Pressure Acting Weird

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Originally Posted by Unclewolverine View Post
Its low but it is the mighty 4.0; for the most part if it stll has oil pressure it will keep going indefinitely. Might throw a quart of Lucas in there every oil change.
I have ran BG Oil treatment with the last 2 oil changes (including current one) and have another 3K to go before I'm due another change. Think next go around I will go up in Viscosity. Probably add some oil treatment too. Hopefully I still have a few years left on this 182K mile 4.0.
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  #26  
Old November 20th, 2020, 16:50
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Tim_MN Tim_MN is offline
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Re: Oil Pressure Acting Weird

Lots Jeeps have driven lots of miles with oil pressure on the low side.
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