So I have a 2000 Cherokee and about 3 days ago I noticed the oil pressure fluctuates a little bit. It usually was in the middle at 40 but now it goes either slightly below that and a little higher than that. At a red light it also goes back down to 40 sometimes but once I give it gas it goes back up about a line and half past the 40 mark. I don't know if I should be worried or what....also, I don't know if this would have any effect on it....but the weather here has gotten ridiculously hot about the same time this started. Any help appreciated!

 

Replace the sending unit down by the oil filter.

 

Ah ok. So there probably isn't an actual problem with my oil pressure though?

 

If the oil pressure stays in the high 30s to say 50s and doesn't drop below that as long as it is running. I would say that the slight difference is just because of hot weather and oil thinning as it warms up.

 

Hey Peter. I am certainly NOT an expert. But my '97 XJ has over 250k miles on it, and the oil pressure runs around 40 psi most of the time. But if it is real hot outside (like in the mid to upper 90's) and the engine has been running for a while, it will drop down to around 12 psi at idle.

I just bought the Jeep from a friend a few months ago. So at first it really freaked me out. But after searching all over the 'net and talking to other XJ owners with... mature... XJ's, this seems to be fairly common and happens to a lot of owners. I found one site with a link to a Jeep article that said it shouldn't fall below the 10-13 range at hot idle and anything at or above that range is fine. I can't seem to find that darn link to post!

I've seen people talk about making sure the oil is fresh, oil filter is new (both of which I have) and oil pressure sensor is working (probably not a bad idea).

So, I don't worry about it any more, and everything runs great.

Let me know if you find out anything different...

 

You want 10psi of oil pressure for every 1000rpm.