Stopped in to ask about this, too.

Is there a standard pressure for XJs? I haven't had mine long and have driven it very little, but mine seems to be on the low side when idling (in the 13 range, as mentioned above) and close to, maybe even topping, 40 on the highway.

Is this normal? I've worried that it's low, but I don't know what's standard.

 

I have a 99 Grand Cherokee,Laredo.With a 4.0 high output.She has 246,000 on her.And my oil pressure is 40 lbs at idle.And 60lbs at highway speeds.Is that good?

 

My 97 xj sport with 203,000 runs 5w30 rotella t6 with k&n filter. Runs about 17psi at hot idle. About 25 psi at normal idle and 50psi runnin down the road

 

She runs at 40 lbs at idle.And 60 lbs at highway speeds. (2000 +rmp) Running Modil 5w30.With 246,000 miles on her.Is my 4.0 a healthy motor?

 

210k miles with pennzoil 10w30 high mileage synthetic blend and wix filter.

Cold idle: 45 psi
Cold at 1500 rpms to 2200: 65 psi

Hot idle: 15 to 20 psi
Hot at 1500 to 2200 rpms: 35 to 40 psi

Also with mobil 1 conventional decrease all psi by 1 to 2 psi and a crappy white oil filter from a quick lube place