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WTF? Oil Pressure guage = crazy....

aroncull

NAXJA Forum User
Location
North Denver, CO
Last couple of days ive noticed that my Oil guage is moving when i throttle..
Idle, red light etc... just fine @ 40 PSI
but whenever i Rev it goes crazy and moves up to 60-70....
It moves in time with my pedal. when im on the highway 65 mph or 2800 rpm or something... its is 65psi

is my sensor sensore? or is there something else going on..
what would cause high oil pressure?
97, 4.0L I6 W/ 125K Miles

i did search but didnt find my answer
TIA
Aaron
 
Mines doing the same thing, acts crazy basicly...
Ill follow the thread. I really dont think its anything to worry about, but I am curious..

Andrew
 
Have you just started paying attendtion to it, or are you positive it didn't do that before? Pretty normal for it to go up with rpms.
 
it used to be pretty static but it has been higher lately and i had never noticed it moving with the rpm....
 
So why would my Oil Guage read so High?
And what does it mean, what could be the worse thing to happen?
Im thinking of the high blood pressure analogy..
Any thoughts?


thanks
aaron
 
I always that was normal.
Here are my numbers.

cold idle 45 psi
warm idle 20 psi
highway 45-55 psi

It moves as i drive, which i beleive is normal. This is a pressure gauge not an oil level gauge. I am sure someone will corect me if i am wrong.

pete
 
jumping in here with my own oil gauge stuff:

40 on the gauge cold idle.
10-20 on the gauge warm idle. (or coasting warm)
slow climb back to 40 under accel.
highest I've ever seen it is about 42 (just past the center mark) while towing. lowest was at the far left of the gauge (just above zero?) idleing after a long trip. (guage was reading nothing, but engine ran fine, no warning lights came on, oil change the next day- clean, no sign of trouble.)

Is this normal for a 4.0l with 125,000+mi?

is it just normal engine wear?-

also, for the first day or so after an oil change (synthetic, 10w30) the gauge will stay right at 40 no matter what the temp. within a few days the gauge goes back to its routine.

someone clue me in here.

thanks-B

Edit: '97 4.0l 125,000, stock
 
Last edited:
My truck apparently has a fresh motor. With new oil I get

Cold start (50 degrees) almost 70psi
Warm idle - just above 25
Cruising - 40ish
 
Its going to move around a little bit as you accelerate...its just oil pressure...not oil level. Mine is 40-60 cold idle, about 20 warm idle and around 40 crusing down the highway. When you really step on it and get the RPMS up high its not unusual at all to see the gauge go up to 60...even when warm.
 
Did it just start getting COOOOOOOLD in Denver? What weight oil are you running?
 
Not to mention the oil pressure sending units on these engines are crap. I have had new ones read wrong and act all funky jumping around. Checked them against a regular real pressure guage and no trouble. You would know if there was a problem and should have sufficient time to shut it down before anything goes boom.

If you want to change your sending unit they're only $15 at the parts store. But your pressures etc sound fairly normal to me.
 
yes it did just get cold here and the oil was changed at the dealer when i had the initail check up after buying it used [pointless btw total wast of money]
so i am not sure what wieght. but on that note thoughts on going synthetic?

Thanks for the clear input 043500 something i will do

thanks
aaron
 
Yup, try a new pressure switch ($30 at Autozone or $67 at dealer). Don't know where Aaron is getting a $15 switch. :)

For years, my pressure was always around 40 psi. Then the gauge started fluctuating a lot. Then it pegged at zero. Then it went the other way and pegged at max, where it stayed for 3 months.

Got a new oil pressure switch, and now all is nice and steady. (NOTE - I bought a new switch back in July, and that did not fix the problem. As it turns out, that new switch was defective. :mad: )
 
I just built & installed a new 4.0 in my cherokee, brand new everything. My oil sits at 75 psi long after its warm. After 15 minutes or so at 185 it slowly goes down to 40 and hangs out right there. The guy that did the machine work to my motor said its fine. After checking everything 100 times on a new motor I have not seen anything that I would consider a problem.
 
Yup, try a new pressure switch ($30 at Autozone or $67 at dealer). Don't know where Aaron is getting a $15 switch. :)

For years, my pressure was always around 40 psi. Then the gauge started fluctuating a lot. Then it pegged at zero. Then it went the other way and pegged at max, where it stayed for 3 months.

Got a new oil pressure switch, and now all is nice and steady. (NOTE - I bought a new switch back in July, and that did not fix the problem. As it turns out, that new switch was defective. :mad: )
A new switch usually solves it, but a lot of times the factory gauges are not accurate. I would get a mech gauge on it and see what it really is.
 
I just built & installed a new 4.0 in my cherokee, brand new everything. My oil sits at 75 psi long after its warm. After 15 minutes or so at 185 it slowly goes down to 40 and hangs out right there. The guy that did the machine work to my motor said its fine. After checking everything 100 times on a new motor I have not seen anything that I would consider a problem.

Are asking if you have a problem or just responding to this 2005 thread?

Minimum good oil pressure would be considered 10 psi per 1,000 rpm, so your readings are good.

If concerned, rent a manual oil pressure gauge and confirm the dash gauge's readings.
 
I had it act insane once when I overfilled it with too much oil. I probably had 6 1/2 quarts in there and not a double sized oil filter. I was driving and all of a sudden it pegged the needle to max like off the scale. I pulled over and drained a quart of oil into a water bottle I had in the XJ and she settled back down to normal again. I had to disconnect the sensor to reset it then all was good. The sensor disconnect is right by the Oil filter on my 94 XJ 4.0L
 
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