Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

Weird oil pressure behavior

Old Jan 7, 2016 | 09:45 AM
  #1  
Yard Dawg's Avatar
Thread Starter
Newbie
 
Joined: Jan 2010
Posts: 19
Likes: 0
From: Mid TN
Year: 1995
Model: Cherokee
Engine: 4.0
Default Weird oil pressure behavior

Could use some advice.

The other nite driving home I noticed the oil pressure gauge was at 0. Everything ran and sounded normal (sorta sounds bad all the time!)

Got home, checked to make sure the wire to the pressure sender wasn't broken and everything looked fine. Started it up and pressure was normal again.
Ran several errands and no problem.
Next morning start it up and gauge was 0 again!
Replaced the sender. Gauge showed normal again last night but 0 again this morning! Added a half quart of 20/50 and pressure has shown normal since.

Again this morning, gauge shows 0. Drove a short distance shut it off. Checked oil and it was fine. Didn't smell bad either. Started back up and oil pressure shows normal again.

Last oil change was last spring. Used 10/30 OReilly brand conventional along with the Lucas additive. Goes through oil fairly regular so it kinda gets a continuous oil change!

I'm currently at 215k miles on the OD!! (Never thought it'd make it this long!!)

Planning to do a complete oil change Saturday. But also wanted to get thoughts on; if it's a problem to use 20/50 in these colder months (middle tn). And also should I still add the Lucas additive along with it?

Any other secret formulas that you'd recommend to keep this thing running a lil while longer??

'preciate any advice y'all can offer.
Reply
Old Jan 7, 2016 | 10:38 AM
  #2  
t.mcginley.jr's Avatar
Seasoned Member
 
Joined: Aug 2015
Posts: 404
Likes: 18
From: New Jersey
Year: 2000
Model: Cherokee
Engine: 4.0L
Default

What Lucas additive are you putting in? Also what kind of oil filter are you running? 20w-50 might be too thick for cold starts

The sending units can act a little weird, the only real way to check is to hook up a mechanical gauge with it running and see what it really at.

Hot idle should be 13psi or greater I believe.
Reply
Old Jan 7, 2016 | 10:54 AM
  #3  
Yard Dawg's Avatar
Thread Starter
Newbie
 
Joined: Jan 2010
Posts: 19
Likes: 0
From: Mid TN
Year: 1995
Model: Cherokee
Engine: 4.0
Default

It's an oil additive. Can't remember the exact name. Comes out like molasses. I was adding it during warmer weather months to the 10/30.

A mechanical gauge would be ideal.

I appreciate the help.
Reply
Old Jan 7, 2016 | 12:44 PM
  #4  
Yard Dawg's Avatar
Thread Starter
Newbie
 
Joined: Jan 2010
Posts: 19
Likes: 0
From: Mid TN
Year: 1995
Model: Cherokee
Engine: 4.0
Default

I'll also add that there has not been any "check engine" light eluminated at any time.

Last edited by Yard Dawg; Jan 7, 2016 at 01:22 PM.
Reply
Old Jan 7, 2016 | 02:33 PM
  #5  
salad's Avatar
Herp Derp Jerp
Premium Member
 
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Default

Oil pressure does not trigger any CEL on these engines, just the Check Gauges light on the dash (if equipped, no idea if the OBD-I models have 'em)

Pop by a parts store and see if they have a rental/loaner oil pressure gauge. Actual 0 PSI oil pressure is quite audible - so you're not really losing pressure. Also falts that legitimately cause that to happen are not intermittent.

And run engine oil... 20w50 has no place in these things outside of the desert... and Lucas Oil Stabilizer (that nutritionally devoid yellow molasses) has no place in any automotive engine period.
Reply
Old Jan 7, 2016 | 02:56 PM
  #6  
Yard Dawg's Avatar
Thread Starter
Newbie
 
Joined: Jan 2010
Posts: 19
Likes: 0
From: Mid TN
Year: 1995
Model: Cherokee
Engine: 4.0
Default

Thanks Salad.
I'll see what the pressure gauge indicates.
Reply
Old Jan 7, 2016 | 03:11 PM
  #7  
salad's Avatar
Herp Derp Jerp
Premium Member
 
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Default

Probably fine lol. I imagine a wire is broken in the harness
Reply
Old Jan 7, 2016 | 03:42 PM
  #8  
Yard Dawg's Avatar
Thread Starter
Newbie
 
Joined: Jan 2010
Posts: 19
Likes: 0
From: Mid TN
Year: 1995
Model: Cherokee
Engine: 4.0
Default

I hope so.
The thing has always sounded like a diesel powered, industrial sewing machine since I got it about 6 years ago!
But it keeps on keepin' on!!
Reply
Old Jan 8, 2016 | 06:54 AM
  #9  
cruiser54's Avatar
::CF Moderator::
 
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Put some Rotella T3 in it. A lighter weight of course.

Use a Wix oil filter.
Reply
Old Jan 11, 2016 | 04:21 PM
  #10  
richamor's Avatar
Junior Member
 
Joined: May 2013
Posts: 79
Likes: 1
From: Piedmont SC
Year: 1989
Model: Cherokee
Engine: 4.0
Default

Mine started doing funny stuff like that. I figured the sending unit was going bad again. I had cleaned it a few times and it seemed to be fine. Until the pressure went to 0 and I kept driving. It started knocking before I got home. The engine is out now for rebuild.

I would either put a mechanical gauge on it to be sure the pump is making pressure or go ahead and change the pump.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
mattsjeep0422
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
5
Jan 31, 2021 01:14 PM
burkett.j
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
4
Jan 4, 2016 05:30 PM
Kung Fuhrer
Aftermarket electrical systems
2
Dec 28, 2015 07:12 AM
70hemicuda
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
2
Dec 23, 2015 08:33 PM
MayerMR
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
12
Dec 19, 2015 08:59 AM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread

All times are GMT -5. The time now is 06:34 PM.