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TJ has Low Oil pressure.... How do I get it back????

5858 Views 19 Replies 15 Participants Last post by  Raz
Hi guys,

I've got some problems...... I need help/advice.

My TJ has been running really low oil pressure for the last couple of months. It all started after I sank er a while back. Although I didn't hydrolock it, I ended up taking in some bog water through the leaking rear main seal.

Since then I have:

Replaced the Rear Main Seal,
Replaced the Oil Pressure Sending Unit,
Ran STP Engine flush through her twice,
Changed the Oil 3 times (over the last 6k miles) currently using 5w30,
Put that fangled Duralube in first and later that shit they use in airplanes that was on the infomercials for your car (name escapes me),
Checked the Main and Rod Bearings for end play etc (all OK),

All of this to no avail.....

Currently, after a cold start the Oil Pressure sits at the 1/2 mark (Forgive me for my laymans terminology as my gauges are in BAR (Metric) rather than PSI), as it warms up it sits at the 1/4 mark. Regardless of wether im driving in town or doing 75 mph it never goes over the 1/4 to 1/3 mark.

Before this all happened, my Pressure used to be at the 3/4 mark when cold, and usually at the 1/2 mark during normal driving, and just over 1/2 during Hwy driving.

Also, I seem to have a bit more Valve Train Tick than before, and she also knocks a bit while i'm maintaining speed on the road (ie. sounds fine during acceleration and deceleration). I also get the "Check Gauges" light when I return to an idle at a Stoplight right after i've been on the Freeway; thing is when I stop the Gauge sits at the 1/8 mark and suddenly drops right off to nothing.

So WTF should I do with it??? Anyone have any suggestions??? i'm wondering if this thing can be salvaged, or should I start looking for a rebuilder???

The only thing I can think of that I havn't replaced is my Oil Pump.... Is this the most likely source of the problem???


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Thanks for the great advice...

i'm gonna give the mech gauge test a whirl. All signs point to the pump :( Thats the price of having fun I guess.

BrandonK, would you part with that stocker you have?? Whats it out of etc.



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LordRatner said:

Ok, tell me this... What engine? 4 or 6? Also, how many miles. Mine does the same thing. I put 20-50 oil in it and it does ALOT better. stays at "the middle" while rpms are above 1500, and dips to 0 and then rises to 1/4 at idle.
Sorry.... Good point :)

115k miles... roughly (180,000kms)

I think I may try running the heavy stuff in the spring.... I used to run 20/50 in my 76 CJ 258, and it seemed to like it.

Just outta curiousity LordR, what you got under the hood...



(EDIT) Doh, you have a 2.5L..... Hmm, wonder if 20/50 will have the same effect on my 4.0l
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