9hundred$ride

I have a 90 Xj 4.0l I've been noticing that my oil pressure when the motor is warmed up for a while the pressure stays at 30 and does go up with engine speed but not much. Its a new rebuilt motor with unknown miles on it. Is there a way to boost the oil pressure and get it where its supposed to be

tjwalker

The problem is not likely to be internal to the engine itself.

Rather, I'd suspect the "oil pressure sending unit" (also known as the oil pressure switch).

It is a very common failure on the 4.0 You can verify pressure if you like by installing a mechanical oil pressure gauge, but if this were mine....I'd probably just buy a new sending unit. And I'd buy it directly from Jeep for the best accuracy/reliability/mating with your factory gauge. Not much more than what an aftermarket unit costs and well worth every penny.

Good luck!

kjc

It's possible your gauge just isn't real accurate. You could check it with a quality pressure gauge. You might try a new oil sender unit.

Click-Click-Pull

What kind of oil filter are you using? After I found out about the orange can of death I switched to K&N and oil pressure was where is should be. Just my .02

9hundred$ride

Right now its a basic frame filter. 10w-30 oil. This is not my DD just a weekend toy

9hundred$ride

How much is a new oil pressure Sensor

Click-Click-Pull

Around $15.00
Please do look into the so called orange cans of death (Fram filters). No BS
I ran Fram for 2 yrs with low pressure and found a thread about them and changed it the same day. Believe it or not it made a huge difference in pressure. K&N gold is all I use now. It has a back flow valve and a welded nut on the back that makes removal so much easier than trying to get a filter wench in there. Just my .02
Good luck and please post what you find! Help out the next guy

9hundred$ride

Should I get that part new from the dealership or can I go to local parts store. Which is better because I'm going to be putting a lift kit on and wanna have the motor in good working order

tjwalker

Buy it from the dealership. It really isn't that much more and is a more reliable unit with better longevity than many aftermarket units.

4x4van

30psi sounds about right.
Too much oil pressure is just heating up the oil for no purpose.
The low pressure light is set for about 5psi on most engines.
Perfectly normal the have the oil pressure drop off at idle on a warm engine.
I have had high mileage engines go for years with less than 10psi at idle.
More pressure is not always a good thing. It means more heat, more foaming and more shear on the oil. Gone are the days of 20w50 and 80psi high volume pumps...

Steve

Gionet

there is no such thing as too much oil pressure, unless you are trying to build high horespower and keep windage down.

get rid of the fram filter, frams suck so bad. You can also add a qt of lucas oil stabilizer to your 10w30 oil, it will boost your oil pressure and do a ton of beneficial things for the motor.

Anything made by lucas in the form of oil is brilliant.

cruiser54

Get rid of that Fram!!! Too many horror stories and other stories like have been posted in this thread. They didn't get the name OCOD for nothing.

Read this:

http://minimopar.knizefamily.net/oil.../opinions.html

CPTslackass

I run Wix on everything. I have 150k on the jeep. 200000 on the intrepid. No problems at all!

9hundred$ride

Thank you guys for all the info on my oil pressure problem. I picked up new k&n oil filter and oil. Had to get oil sensor order from the dealership should be in before the weekend. I will get back with you guys and see if there was any change in oil pressure.

cruiser54

Change just the oil filter while waiting for the sender. I'm very curious.