bajaxj

I'm borrowing my sister in law's XJ while the insurance company decides the fate of mine. Anyway when I brought it home I noticed that the oil pressure fell to 10psi(this was after about an hour of highway driving). I checked the oil level before living her place and it was full. What do you guys suggest I start with? I figure it could be the sensor or the pump(I'm hoping is the pressure sensor). Any suggestions will be appreciated. Thank you.

DieselD

I'd say the sensor is a good place to start.

RTorrez1

What was the pressure before you noticed that it was at 10?

bigbadon

Welcome to the 4.0 low oil pressure club. 10psi at idle is not bad. Engine is not under stress at idle therefore it doesn't require a while lot of flow. I've been running 4 psi on my very busy daily driver for years.

Firestorm500

Yeah, don't worry about it. 10 PSI indicated, not verified, is nothing to be concerned over.

Even if it really is 10 PSI under that condition, nothing is being hurt.

Trimmy

About 5 years ago I bought a 99 cherokee very very very cheap that was in perfect shape and low miles because it only had 10psi at idle. Took it home changed the oil and filter. It had perfect oil pressure after that. He took it to the same shop to have the oil changed and they probably never changed the filter once.

bajaxj

At highway speeds it maintained at 40psi. I was thinking of changing out the sensor but first I'm going to ask who changed the oil last. If it was a shop, I'll go ahead and change the oil first then go for the sensor if it doesn't change. Thanx for your replies, greatly appreciated.

tjwalker

What year XJ are you referring to here?

The reason I'm asking is that the 00-01 have the infamous 0331 cylinder head which can (not always) crack, which if not caught early enough, can and will lead to eventual low oil pressure.

But I digress. For a low oil pressure reading on the dash gauge, I ALWAYS verify. It's easy. Get a mechanical oil pressure gauge (can be rented from many parts stores; call around) and temporarily replace it where the oil pressure sending unit resides.

Then you'll know with confidence. Good luck and keep us updated!

bajaxj

That would of been a good way to start of my thread
It's a 97, has about 154,XXX miles.

s346k

my 97 shows anywhere from 10-25 lb at idle and 40-50 above 1200 rpm on the dash

mech gage says 25 at idle 55 on the road.

check it against a mechanical gage first

Firestorm500

Actually, it sounds like someone was using the hated FRAM filter.