Oil pressure...

[01XJ]

What should be normal oil pressure at idle? in a XJ.. when im on the road it is up around 40 or alittle higher,When im stopped at a idle im barely at 10 is this normal? The oil is up not low and it is fresh just did a oil change but it dont make a difference if i change it or not

 

[anvil]

I've always heard you need at least 10 PSI per 1000 RPM. You should be fine.

 

[mbryson]

Mine was like that. I was always nervous about it, but it did that until I sold it with 185K on the clock........ Never had an oil problem.

 

[Jeeptj98]

What should be normal oil pressure at idle? in a XJ.. when im on the road it is up around 40 or alittle higher,When im stopped at a idle im barely at 10 is this normal? The oil is up not low and it is fresh just did a oil change but it dont make a difference if i change it or not

When I had my 2000 XJ it did this exact same thing I kept taking in to the dealership for warranty repair, they replaced the Sensor a couple of times but it never fixed it finally they just told me that is the way they are

 

[Hickey]

I would'nt worry about it unless you see a change. Some engines run high, some run low.

 

[RockMonkey]

Jeep motors seem to be fine as long as you have some oil pressure.

 

[01XJ]

Sweet this is good news thanks for all the info guys now i dont have to worry

 

[Brett]

I dunno....I've been worried about mine lately in my XJ. It used to run at about 30 lbs of pressure at idle and lately it's been dropping below 20, which to me is not normal. Freeway speeds it would usually average 50 lbs and it's now down around 40 or less.

I'm thinking that I might be losing my oil pump or that the sensor is going bad. I'll go the easy way and change the sensor and see what happens for now.

 

[mowlasley]

Did it work down to 10 lbs. gradually, or just drop off all of a sudden?

I ask because my oil pressure suddenly dropped in my 4.0 and I hooked up a mechanical guage to see if the dummy light was right. It was running at about 8 pounds. 2 different mechanics told me that the engine was just worn out and that worn bearings would let the pressure drop. One suggested I try to pawn it off as a trade in.

I ended up pulling the oil pan to find the oil pump only attached to the block with one of the two bolts, so it was not aligned with the passages in the block. The other bolt was in the bottom of the pan. I ended up just replacing the oil pump, since I was in there anyway, and my oil pressure issues were solved.

 

[01XJ]

Did it work down to 10 lbs. gradually, or just drop off all of a sudden?

I ask because my oil pressure suddenly dropped in my 4.0 and I hooked up a mechanical guage to see if the dummy light was right. It was running at about 8 pounds. 2 different mechanics told me that the engine was just worn out and that worn bearings would let the pressure drop. One suggested I try to pawn it off as a trade in.

I ended up pulling the oil pan to find the oil pump only attached to the block with one of the two bolts, so it was not aligned with the passages in the block. The other bolt was in the bottom of the pan. I ended up just replacing the oil pump, since I was in there anyway, and my oil pressure issues were solved.

It dont drop real fast but it dont take only a few second to go down to 10 or lower when you stop...first thing in the mornings it it is up around 50 at idle and as it warms it heads down..i have about 58k on the motor im hoping it aint the motor getting ready to eat it :-\ i will try a new sensor and then if that dont work i will pull the pan like you did and check everything..what else would i expect its a Heep

 

[mowlasley]

What I meant was this: Have you noticed the oil pressure slowly working its way down for the last year, or did it suddenly drop yesterday?

 

[BCGPER]

ok, dumb guestion here but...... What weight oil are you guy's running? As an engine wears, it's going to lose oil pressure due to increased bearing clearances, and oil pump gear wear. I'm guessing you're all running the "new engine" recomendation of 10-30? Time to go thicker when you get to the 100K range. A good say 15-40 or straight 30 will cure that idle oil pressure problem I'll bet. I'd change the oil before messing with pressure senders and such.

 

[Brett]

ok, dumb guestion here but...... What weight oil are you guy's running? As an engine wears, it's going to lose oil pressure due to increased bearing clearances, and oil pump gear wear. I'm guessing you're all running the "new engine" recomendation of 10-30? Time to go thicker when you get to the 100K range. A good say 15-40 or straight 30 will cure that idle oil pressure problem I'll bet. I'd change the oil before messing with pressure senders and such.

I've been running 10w30, but as I said, until the last month, I was running normal oil pressure, so I don't think that it's anything to do with the weight of my oil.

 

[gijohn40]

everything is normal...

at idle your oil pressure is going to be around 10 on any engine that has mileage on it... this is normal... and at speed it will go up to 40 or so.. nothing is wrong... unless you have what I have on my old 4.2 where in the morning when the oil is cold it idles at 30 and then drops off to almost nothing as it heats up...

Don't worry about it.... but watch it!

 

[waynehartwig]

I've always heard you need at least 10 PSI per 1000 RPM. You should be fine.

Exactly...

But there are a number of reasons for drop in oil pressure - worn bearings, worn pump, bad filter, bad bypass, etc...etc... If it just one day dropped all of a sudden, I'd look at the bypass spring - it may have broke or came out. But while you are in there looking at that, you might as well put a new Melling oil pump in! DO NOT buy a cheapy down at Vato-zone. Get a good one or you could have additional problems shortly down the road.

Also, be careful with high volume pumps. If you don't change the pump drive, the HV pump could sheer it and cause the pump not to work at all. Also, some engines have problems with draining the oil back to the pan. With a HV pump, that could creat problems there as well with either oil never making it back down and causing the pump to suck air or oil to come out your breather or etc.