88GTBlack

My xj gets no attention cuz my Stanford gets it all but I run syn oil 10 30 w a champ filter and oil pressure keeps gettin lower and lower.. Today it idled at 16psi. My valve cover gasket has slight leak but what gives?

Mobil 1 oil change w mobil1 filter will be put in it Friday and I always run two quarts thru with drainplug out WTF gives.

To help you guys out more, it still hiccups at idle

89Laredo

No need for the 2qt drain, thats a waste of good (and expensive) oil. Anything in the bottom of the sump will get caught in the filter.
Try running 15w40 or 10w30 Rotella Synthetic with whatever filter you want and see if your OP goes up any.
Diesel oil has more detergents and zinc in it anyway, its better for your motor. Current SM oils do not have enough zinc and we are forced to pick other (non standard) oils or use a ZDDP additive for our flat tappet cams.

It also may be a failing Oil Pump. IIRC, 13psi is the low side in the FSM at idle.

Bustedback

A valve cover gasket will not effect the oil pressure. Replace the sending unit before you start ripping the oil pan off.

snackpackXJ

i am also having this problem with my jeep... and have replaced my sending unit.. i am mechanically inclined and new to jeeps and wondering how hard it is to replace the oil pump on the stright 6?

djb383

16 PSI verified accurate at hot idle seems OK....general rule of thumb is 10 PSI minimum for each 1000 RPM. Thicker oil flows slower, runs hotter, increases parasitic power loss and does not equal better lubrication......increased flow rate does.

robertj

16 psi is well within factory tolerances for oil pressure on these 4.0s at idle.

Willys55

correct
also correct

by the way put a real guage on it for an ideal pressure reading. sending units vari by 3 psi +/-

Programbo

My 94' idles at around that after it is warmed up and has been doing that for years. You can swap out the instrument cluster to the "dummy lights" and then you won`t have to see the engine oil level

Scooter86

I have this thread which is pretty similar. Mine idles at 5-10psi...
https://www.cherokeeforum.com/f2/oil...e-issue-45052/

JrRifleCoach

Old school rule of thumb; 10psi for each 1000RPM.

2.5TURBO

The oil pan is a B***h! You have to disconnect the axle and jack up the body. The chilton's manual says to unbolt the motor and jack it up instead. I've done it both ways and the axle was easier. You do need to be careful so your jeep doesn't fall when jacking it up that far. The pan ALWAYS comes out easier than going back in.

The oil pump is easy to get to after the oil pan. I believe 2 bolts? The only hard part is getting the pickup tube out of the old pump. Just use a hammer if it's really stuck! Not on the tube though, on the oil pump. DUH!