Hi everybody. I have a 99 xj with 4.0 and aw4. My question is that my oil pressure gauge always points to the maximum 80 psi. Even when I'm idling or going 75 mph on highways. I'm wondering if the gauge isn't working or my oil pressure switch isn't reading the pressure properly?
I use SAE 30 In the engine. And in case anyone's wondering the clock read 120k miles
Anyone else have the same problem?

Thanks!

 

Bad oil pressure sending unit.

 

Is there a way I can test it to confirm that it's malfunctioning?

 

Twenty five bucks at the parts store and takes ten minutes to change with an adjustable wrench. It's located near the oil filter.

 

You can always rent a mechanical pressure gauge to verify your oil pressure. But most of times the the sending unit goes bad it will max out.

 

Alright thanks. I ll get new unit since its that cheap. Thanks everybody

 

Just replaced the oil pressure switch today and the oil gauge read normal operating pressure instead of being stuck at max 80 psi all the time, thanks everybody for all their input.

 

That's what everyone is here for. Glad you got it taken care of.

 

Yup! Way better than going to the stealership

 

You're running SAE30 oil???

 

Yes sir. Always have in all of my vehicles. Never had a problem with that

 

Before u ask, the gauge have been that way since it was rescue from the boneyard. I don't think sae 30 have anything to do with the malfunctioning oil pressure switch though.