greenmachine777

Hey guys. I recently bought a 93 Cherokee Sport- 4.0. has 169xxx, unrebuilt to my knowledge, runs good except it's behaving strangely. So it's been showing high oil pressure when the level is safe on the dipstick. Additionally, when i filled it up to the safe mark, it likes to burn oil, which i understand is common when oil is overfilled. I'm going to change the oil and filter as i understand the filter can cause high pressure issues. If anyone has had a similar experience please chime in and let me know what the problem may be

x91evo

The indash gauge is showing high pressure?
Its the sending unit for the gauge, very common problem

McCaffrey

^^^ Yeah. Higher than expected oil pressure would be like having higher than expected horse power. Probably your gauge.

tjwalker

You don't mention any actual numbers. Devil is always in the details.

The oil pressure spec for the 4.0 is shown below. If you are in this range, you're fine. If you still feel you're high, the most common cause is a bad "oil pressure sending unit", located directly above the oil filter. If you're so inclined, you can always verify your pressure by temporarily installing a mechanical oil pressure gauge where the oil pressure sending unit resides. These gauges can often be rented from a parts store.

*Not less than 13 psi at HOT idle

*Between 37-75 psi OVER 1600 rpms

greenmachine777

It tends to run about 60 @ idle when cold. When revved up it goes up to about 70, 75. The guy i bought it from didn't seem to mechanically inclined and had let it run about 2 qts low. The gauge was reading about 20 idle, 25 at 2 grand before i topped it off so this would lead me to believe that the gauge at least works to some degree.

greenmachine777

I also figured out that i HAD probably overfilled it when it was burning off oil. I made the mistake of dipsticking it hot. I adjusted the oil level cold and rechecked and its ok now and not smoking. My only concern now is the hi pressure. I'll look into the mechanical pressure gauge.

Muaddib420

I would change your oil and filter. 10W30 and a mopar filter. You can get them at Walmart now. Six quarts.

Then change your oil pressure sending unit. BWD from any parts store for $25. Five minutes to change it with an adjustable wrench. Then see what your pressures are.

Cherokee

sounds like its in spec to me.

no harm in putting a high quality filter on though, be careful that your filter does not have a cardboard anti drainback valve like FRAM filters have. I use purolator pure one filters.

HudsonN

Avoid "Fram" Filters.

I'd rather have high oil pressure than low oil pressure.

Nothing-2-Deep-4-Cherokee

Your dashboard gauge could be faulty and it just isnt working properly