I know generally that the bearing tolerances get further apart causing pressure drop, but how do I cure this?

I just changed my oil with Mobile 1 5w30 because I had it lying around, and my hot idle psi is hovering right at 15psi which is kind of worrying. With Rotella T6, hot idle psi goes up to 20psi or so.

I am going to replace my oil pressure sending unit and clean out the passage just to be sure, but mine looks fairly new and not too dirty around it so I suspect that it is fairly accurate.

But are there any solutions to this other than replacing the bearings (which obviously constitutes a partial engine rebuild at the least)? I am going to be replacing my RMS and oil pan gasket, and was wondering if changing the oil pump would be beneficial in any way. I am also afraid that the replacement pump could be defective and end up killing my motor if I accidentally starve it of oil (since the current pump has lasted 180k miles with no issues thus far).

Motor is pretty clean after several cleaning oil changes with either T6, or MMO added to the oil, and no real sludge issues. I havent removed the valve cover yet, but it looks pretty sludge free through the oil filler hole.

Someone tell me what to do

EDIT:
And before I get flamed, I know that 13 PSI is within "operating spec", but it does seem pretty low to me and I want this motor to last me a long time. I am going to switch to T6 after I run this oil a thousand miles or so just so it doesnt go to waste, but my roommate's WJ 4.0 never dips below 40psi (though I dont know if it has a real oil pressure sender or an idiot light)

 

First measure the pressure with a dedicated gauge in place of the sending unit. If you are within minimum spec there, why would you want to take apart your engine?

 

x2 15 psi with 5-w-30 is good. I have stated this point many times....don't get too worked up over hot idle pressure. Be more concerned if you have low pressure above 1500 rpm.

 

What brand of oil filter both times? Same or different?

 

like posted above.. you are within spec

The only way I can think of at the moment (if you are running a quality filter) to build up operating temperature oil pressure, is to purchase an oil with a thicker HOT viscosity... like the T6, but this is really not necessary

Having you pressure tested independently from the factory gauge is always the best insurance...

I would run T6 for its benefits... not to bring up the pressure...

 

czech that filter. Also make sure the sending unit is accurate, oil contamination or blocked galley to it will cause goofy ****.

 

Napa 1515 filter always.
Hot pressures are 35psi @ 1500rpm, 40psi 2000+ rpm

So idling in traffic with the gauge wobbling on 13psi is totally OK? It just makes me nervous is all.

And this basically all loops back to weather or not I should replace the oil pump while I have the oil pan off.

I'll buy a mechanical gauge to verify with though.

 

Test before anything. FSM says if it dips below 13 PSI at hot idle on a 30-weight oil it's repair-worthy.

 

YES,yes,yes. Benchmarking engine condition at idle pressure is iffy. Jeep specifies 13psi at 650 rpm but alot of engines manufactures use a higher rpm (1500 or greater) to spec oil pressure. It is completely possible to have minor wear and still be within spec.to drop pressure at idle. For example if lifter bores were only worn .0005" oil pressure at idle would drop 50% but the engine would be in no risk of failure.
There have been plenty of cases of good running engines that were rebuilt b/c of low oil pressure at idle only to still have low pressure after the rebuild.

 

so how would one do this guage test to verify oil pressure...
cuz seems I need to do it, and I don't know anything about it

 

Oil pressure sending unit is right above the oil filter. Unscrew OPSU with something like a half-inch wrench, screw in testing kit, start engine. Should be directions with the kit.

 

Remember that oil pressure is resistance to flow.

High oil pressure is not a good thing. I think your oil is flowing better than ever at idle with 5W-30 Mobil 1. You have helped your engine, not hurt it.

I don't believe your oil pressure reading is a cause for concern at all.

 

what if you idle at 0?
cuz that's me


and thanks salad, that's all I needed to know

 

EXACTLY High pressure represents LOW flow. Flow is what lubricates and cools things.

 

To update this thread, I cleaned out the oil passage and repeated the test with a mechanical gauge. I dont have enough hose to read it while driving, but at a very hot idle, it still reads ~15-20PSI with Rotella T6 in it.

I guess that is OK for me as long as it is OK for the motor. Just want to make her last as long as I can