[LRMark26]

Is running at high oil pressure bad? What kind of damage may it cause?

My oil pressure has been reading 80psi since I changed my oil last week. Changed oil (10W-30) and Oil Filter. It is 80 as soon as I start it. After driving about 20 miles, side roads and expressway, 10mph - 65mph, it will lower to about 65psi when I slow down getting off the expressway and will go back up slightly.

I looked through the service manual and could not find anything regarding High Oil Pressure only Low. I know the pressure relief is at 75psi, obviously this is not working.

Any thoughts?

(2000 Wrangler, 4.0 Manual)

 

[TjTheo]

How much oil did you put in it?
The oil pressure sensor is known for going bad in the wranglers but since this happened right after you changed your oil it a little too much of a coincidence.

You're supposed to put 6 quarts in the 4.0, most likely less because the oil doesn't drain all the way when you change it.

 

[LRMark26]

I put in 6 qts, watched the dip stick as I added the last qt. Checked the stick again the other day and is in the safe zone.

 

[Gorving3]

A couple years ago my 2001 Wrangler 4.0 engine pegged the oil pressure right after climbing a steep jeep trail to about 11,000 feet and nearly scared me to death when I noticed the gauge. I knew that extremely high oil pressure can cause engine damage and seal leaks so I wasn't sure whether to continue on or turn around and coast back down but I shut the engine off for a few minutes while we got out and stretched. When I restarted the engine after a few minutes everything was back to normal and has been ever since. Guess the relieve valve sticks for a little bit then releases. Hope it doesn't happen again.

 

[CapnDean]

Check your pressure relief and next replace your sending unit. See what happens then.

 

[pokey]

I think it's the sending unit. Mine also spiked at 80 after an oil change, probably a co-incidence. Our motors aren't known for faulty relief valves, but they are notorious for faulty oil gauge readings. I still haven't changed my sending unit and it still reads 80 most of the time. I'm going to fix it soon. First try unplugging the sending unit and spray it with WD40 and shake the excess off. Sometimes that works.

 

[Gorving3]

I think it's the sending unit. Mine also spiked at 80 after an oil change, probably a co-incidence. Our motors aren't known for faulty relief valves, but they are notorious for faulty oil gauge readings. I still haven't changed my sending unit and it still reads 80 most of the time. I'm going to fix it soon. First try unplugging the sending unit and spray it with WD40 and shake the excess off. Sometimes that works.

On the 4.0 engine about where would I look for the oil gauge sending unit?

Thanks for the information.

 

[cork1958]

I saw my oil gauge go some what ballistic one time (about 65psi) just cruising down the road shortly after I left the house.

I stopped at the gas station on my way to my brothers and when I got back in it and took off, it went back to normal. Haven't seen it do that again yet. Did freak me out though!

 

[Plowboy1970]

I just had mine today go the other way on my 97 4.0 auto. 0 at idle and hold 40 running. Put in a new sender. Now 35-55 running. Change the sender.

 

[mybadford]

I know this is an old post. I just googled TJ reading 80psi and this came up. My gauges reads 80psi with the key on and engine not running. I initially noticed the high oil pressure with the engine running but has a rod knocking. I figured it would read low since the tight bearing clearance isn't there and oil would easily flow past the spun bearing.

 

[jkp]

Your sending unit is probably bad.