oil pressure?
#16
Senior Member
Joined: Dec 2011
Posts: 669
Likes: 0
From: Central Arkansas
Year: 1996
Model: Cherokee
Engine: 4.0L
Originally Posted by tjwalker
Your numbers are fine and well within the spec listed below. Drive it.
*Not less than 13 psi at HOT idle
*Between 37-75 over 1600 rpms
*Not less than 13 psi at HOT idle
*Between 37-75 over 1600 rpms
#17
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 13
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
#18
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,565
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Before you spend any more time or money on this issue, get rid of the Fram!!! No kidding.
Put a Wix or Napa Gold on the Jeep.
Change just the filter. Don't worry about losing much oil. The Fram doesn't hold any in it hardly because of it's POS anti-drainback valve.
Put a Wix or Napa Gold on the Jeep.
Change just the filter. Don't worry about losing much oil. The Fram doesn't hold any in it hardly because of it's POS anti-drainback valve.
#19
Thread Starter
Newbie
Joined: Feb 2010
Posts: 29
Likes: 0
From: Newaygo, MI
Year: 98
Model: Cherokee
Engine: 4.0
I'm gonna pick up a filter tonight and see what that does for me. Hopefully its back up to snuff haha I can't believe I didnt realize it probably happened a couple hundred miles after I changed oil last
#20
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,565
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
If it's the Fram causing it, you won't be the first and probably not the last.
#21
Thread Starter
Newbie
Joined: Feb 2010
Posts: 29
Likes: 0
From: Newaygo, MI
Year: 98
Model: Cherokee
Engine: 4.0
Its not the fram, I changed it and its still low.. While I was wheelin last weekend and the temp creeped up a little above 210 it was dropping to 10psi at idle but still 40 after 1500rpm
#22
Junior Member
Joined: Sep 2010
Posts: 93
Likes: 0
From: Duluth, Minnesnowta
Year: 2000
Model: Cherokee
Engine: 4.0L
Mine runs at ~13psi idle and 25ish when cruising at highway speed. Has for almost two years and 15k miles with no issues? Think I should change the pressure sending unit and see if the read is different? Running Amsoil 10w40 and Amsoil FIlter.
#24
Thread Starter
Newbie
Joined: Feb 2010
Posts: 29
Likes: 0
From: Newaygo, MI
Year: 98
Model: Cherokee
Engine: 4.0
Originally Posted by freestylekid33
I think this weekend I'm gonna try a sending unit, hopefully that fixes it..
#25
Junior Member
Joined: Aug 2011
Posts: 40
Likes: 0
From: Michigan
Year: 1996
Model: Cherokee
Engine: 4.0 H.O. inline six
Good thread! I recently noticed mine dropping to 18-20 at hot idle, then jumping back up to 38-40 as soon as I accelerated. Good to know I'm still within acceptable range. Phew!! BTW freestylekid33, I see you are from Newago! Bet we've hit many of the same trails around there!
#26
In my experience thus far with now two XJ's there are 4 things I have found related to oil pressure issues.
1) The best oil sending unit that you can get for the money is the mopar one straight from the stealership for around $50 and it's guaranteed to fit the first time.
2) Cracked wires, slightly bent pins, oil, water or any other means of shorting the wires out for the sending unit will cause the gauge to go haywire.
3) That the factory oil pump sounds like it's crushing rocks when pulled out at 180k. This was the pure cause of the problems in the white XJ and a mere oil pump fixed the issue because it was an old TXDOT vehicle and was well maintained.
4) The oil pressure in my new XJ is a combination of bad maintenance and bad oil pressure. Thus, all of my bearings have been damaged. I'm currently in the process of changing all of them with the engine still in the Jeep. Rods are done and I will start the mains tomorrow. Can get video of the best way I have found to get the top main bearings out if needed.
While issue #4 is a LOT more intensive and you have to know what the bloody hell you are looking at when it comes to bad/good wear... It is still a major issue.
1) The best oil sending unit that you can get for the money is the mopar one straight from the stealership for around $50 and it's guaranteed to fit the first time.
2) Cracked wires, slightly bent pins, oil, water or any other means of shorting the wires out for the sending unit will cause the gauge to go haywire.
3) That the factory oil pump sounds like it's crushing rocks when pulled out at 180k. This was the pure cause of the problems in the white XJ and a mere oil pump fixed the issue because it was an old TXDOT vehicle and was well maintained.
4) The oil pressure in my new XJ is a combination of bad maintenance and bad oil pressure. Thus, all of my bearings have been damaged. I'm currently in the process of changing all of them with the engine still in the Jeep. Rods are done and I will start the mains tomorrow. Can get video of the best way I have found to get the top main bearings out if needed.
While issue #4 is a LOT more intensive and you have to know what the bloody hell you are looking at when it comes to bad/good wear... It is still a major issue.
#27
In my experience thus far with now two XJ's there are 4 things I have found related to oil pressure issues.
1) The best oil sending unit that you can get for the money is the mopar one straight from the stealership for around $50 and it's guaranteed to fit the first time.
2) Cracked wires, slightly bent pins, oil, water or any other means of shorting the wires out for the sending unit will cause the gauge to go haywire.
3) That the factory oil pump sounds like it's crushing rocks when pulled out at 180k. This was the pure cause of the problems in the white XJ and a mere oil pump fixed the issue because it was an old TXDOT vehicle and was well maintained.
4) The oil pressure in my new XJ is a combination of bad maintenance and bad oil pressure. Thus, all of my bearings have been damaged. I'm currently in the process of changing all of them with the engine still in the Jeep. Rods are done and I will start the mains tomorrow. Can get video of the best way I have found to get the top main bearings out if needed.
While issue #4 is a LOT more intensive and you have to know what the bloody hell you are looking at when it comes to bad/good wear... It is still a major issue.
1) The best oil sending unit that you can get for the money is the mopar one straight from the stealership for around $50 and it's guaranteed to fit the first time.
2) Cracked wires, slightly bent pins, oil, water or any other means of shorting the wires out for the sending unit will cause the gauge to go haywire.
3) That the factory oil pump sounds like it's crushing rocks when pulled out at 180k. This was the pure cause of the problems in the white XJ and a mere oil pump fixed the issue because it was an old TXDOT vehicle and was well maintained.
4) The oil pressure in my new XJ is a combination of bad maintenance and bad oil pressure. Thus, all of my bearings have been damaged. I'm currently in the process of changing all of them with the engine still in the Jeep. Rods are done and I will start the mains tomorrow. Can get video of the best way I have found to get the top main bearings out if needed.
While issue #4 is a LOT more intensive and you have to know what the bloody hell you are looking at when it comes to bad/good wear... It is still a major issue.
#28
Member
Joined: Mar 2012
Posts: 205
Likes: 0
From: Severance, Colorado
Year: 1999
Model: Cherokee (XJ)
Engine: 4.0 litre, line 6
Just a note anyone with a 00 or 01XJ has the 0331 head and low oil pressure can SOMETIMES be a sign of the head bein cracked....just so ya know
#29
Today i went from Castrol 15/30 and a fram to a Napa Gold and some Delo 400 15/40... My XJ has 260k...
My normal pressures were between 25-30 hot, and 60 cold....
Now my pressures at 65 cold and 38-just over 40 hot..
I did notice that the bad ugly dry bearing sounds went away apon starting (yay my oil filter didnt drain out!!)
It feels more peppy too, and runs alot smoother..
My normal pressures were between 25-30 hot, and 60 cold....
Now my pressures at 65 cold and 38-just over 40 hot..
I did notice that the bad ugly dry bearing sounds went away apon starting (yay my oil filter didnt drain out!!)
It feels more peppy too, and runs alot smoother..
#30
hot idle oil presure dropped to 12lbs.Replaced pump with high volume milling pump. Hot idle now 27 with 15-40 and a wix. 200 thousand on engine. Engine is smoother and pulls better.Never did hear any noise. Just like the old days oil pump should be considered a normal wear item.Just food for thought