Oil Pressure Questions
Thread Starter
Member
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver, CO
Year: 2000
Model: Cherokee
Engine: 4.0 Inline 6
Hey guys, Ive been reading a bunch about oil pressures on here, and it seems like I have been hearing things all over the board.
I read that it should be around 40 at cold idle and down to 13-20 at temp idle. However, mine never varies that much. Mine goes up to 40 at start, and up to 50ish when accelerating, but never goes down near 20, let alone 13. Am I good, or should I look into this? Thanks
I read that it should be around 40 at cold idle and down to 13-20 at temp idle. However, mine never varies that much. Mine goes up to 40 at start, and up to 50ish when accelerating, but never goes down near 20, let alone 13. Am I good, or should I look into this? Thanks
You're golden!
The idle pressure per FSM is 13.
Operating pressure for above 1600 rpm is 37 to 75.
40 on acceleration is fine.
Oil pressure needs to be relatively consistent so if you see wild fluctuations you need to diagnose if you are seeing the correct oil pressure and what would cause the fluctuations.
Everyone has different issues with their engines such as wear, oil type, filter type etc. That's why you see varying opinions on what is correct pressure.
The idle pressure per FSM is 13.
Operating pressure for above 1600 rpm is 37 to 75.
40 on acceleration is fine.
Oil pressure needs to be relatively consistent so if you see wild fluctuations you need to diagnose if you are seeing the correct oil pressure and what would cause the fluctuations.
Everyone has different issues with their engines such as wear, oil type, filter type etc. That's why you see varying opinions on what is correct pressure.
Thread Starter
Member
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver, CO
Year: 2000
Model: Cherokee
Engine: 4.0 Inline 6
You're golden!
The idle pressure per FSM is 13.
Operating pressure for above 1600 rpm is 37 to 75.
40 on acceleration is fine.
Oil pressure needs to be relatively consistent so if you see wild fluctuations you need to diagnose if you are seeing the correct oil pressure and what would cause the fluctuations.
Everyone has different issues with their engines such as wear, oil type, filter type etc. That's why you see varying opinions on what is correct pressure.
The idle pressure per FSM is 13.
Operating pressure for above 1600 rpm is 37 to 75.
40 on acceleration is fine.
Oil pressure needs to be relatively consistent so if you see wild fluctuations you need to diagnose if you are seeing the correct oil pressure and what would cause the fluctuations.
Everyone has different issues with their engines such as wear, oil type, filter type etc. That's why you see varying opinions on what is correct pressure.
Hey guys, Ive been reading a bunch about oil pressures on here, and it seems like I have been hearing things all over the board.
I read that it should be around 40 at cold idle and down to 13-20 at temp idle. However, mine never varies that much. Mine goes up to 40 at start, and up to 50ish when accelerating, but never goes down near 20, let alone 13. Am I good, or should I look into this? Thanks
I read that it should be around 40 at cold idle and down to 13-20 at temp idle. However, mine never varies that much. Mine goes up to 40 at start, and up to 50ish when accelerating, but never goes down near 20, let alone 13. Am I good, or should I look into this? Thanks
Is your engine noisy? If not I would not worry too much. Mine runs around 4 psi and has for a long time. Oil flow is what is important....as long as oil is being delivered to the bearings pressure is not a great concern. Oil pressure is used to benchmark engine wear but even a loose worn engine can run a very long time if you take it easy.
Keep an eye on coolant loss and listen for any increase in engine noise.
Thread Starter
Member
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver, CO
Year: 2000
Model: Cherokee
Engine: 4.0 Inline 6
What weight oil? How many miles? Do you have to add coolant once in awhile?Unless you verify with a mechanical gage the dash gage is useless.
Is your engine noisy? If not I would not worry too much. Mine runs around 4 psi and has for a long time. Oil flow is what is important....as long as oil is being delivered to the bearings pressure is not a great concern. Oil pressure is used to benchmark engine wear but even a loose worn engine can run a very long time if you take it easy.
Keep an eye on coolant loss and listen for any increase in engine noise.
Is your engine noisy? If not I would not worry too much. Mine runs around 4 psi and has for a long time. Oil flow is what is important....as long as oil is being delivered to the bearings pressure is not a great concern. Oil pressure is used to benchmark engine wear but even a loose worn engine can run a very long time if you take it easy.
Keep an eye on coolant loss and listen for any increase in engine noise.
Senior Member
Joined: Sep 2008
Posts: 897
Likes: 12
From: Sioux Falls, SD
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
On your 2000, check the oil for coolant. If you have the 0331 head, you should check for leaks.
My '92 has about 2 PSI at hot idle and MAX 20PSI on the interstate runnin 70-75mph. Been that way for 4 years now. Runs like a champ still. I DID replace the oil pump a few years ago with a Melling HV one. I toss in what ever is on sale 10w30 oil. 250K on the clock now.
Just got back from a 1000 mile trip towing my 10 foot utility trailer with boat and 1100 motorcycle.
Engine ran like a top the whole time. Having fuel pump issues now tho.
Keep an eye on the coolant level and for "milky" oil... Recommended oil changes and you will be good to go for a long time.
My '92 has about 2 PSI at hot idle and MAX 20PSI on the interstate runnin 70-75mph. Been that way for 4 years now. Runs like a champ still. I DID replace the oil pump a few years ago with a Melling HV one. I toss in what ever is on sale 10w30 oil. 250K on the clock now.
Just got back from a 1000 mile trip towing my 10 foot utility trailer with boat and 1100 motorcycle.
Engine ran like a top the whole time. Having fuel pump issues now tho.

Keep an eye on the coolant level and for "milky" oil... Recommended oil changes and you will be good to go for a long time.
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Thread Starter
Member
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver, CO
Year: 2000
Model: Cherokee
Engine: 4.0 Inline 6
On your 2000, check the oil for coolant. If you have the 0331 head, you should check for leaks.
My '92 has about 2 PSI at hot idle and MAX 20PSI on the interstate runnin 70-75mph. Been that way for 4 years now. Runs like a champ still. I DID replace the oil pump a few years ago with a Melling HV one. I toss in what ever is on sale 10w30 oil. 250K on the clock now.
Just got back from a 1000 mile trip towing my 10 foot utility trailer with boat and 1100 motorcycle.
Engine ran like a top the whole time. Having fuel pump issues now tho.
Keep an eye on the coolant level and for "milky" oil... Recommended oil changes and you will be good to go for a long time.
My '92 has about 2 PSI at hot idle and MAX 20PSI on the interstate runnin 70-75mph. Been that way for 4 years now. Runs like a champ still. I DID replace the oil pump a few years ago with a Melling HV one. I toss in what ever is on sale 10w30 oil. 250K on the clock now.
Just got back from a 1000 mile trip towing my 10 foot utility trailer with boat and 1100 motorcycle.
Engine ran like a top the whole time. Having fuel pump issues now tho.

Keep an eye on the coolant level and for "milky" oil... Recommended oil changes and you will be good to go for a long time.
CF Veteran
Joined: Sep 2011
Posts: 4,172
Likes: 4
From: Riviera, Texas
Year: 1998 Sport
Model: Cherokee
Engine: 4.0
I wish I had oil pressure like that. Mine is a little low but still not to the point that I have to worry. It is always good to stick a mechanical gauge to verify you pressure if your not sure if it's correct.
Thread Starter
Member
Joined: Mar 2011
Posts: 190
Likes: 0
From: Denver, CO
Year: 2000
Model: Cherokee
Engine: 4.0 Inline 6
Thanks
CF Veteran
Joined: Sep 2011
Posts: 4,172
Likes: 4
From: Riviera, Texas
Year: 1998 Sport
Model: Cherokee
Engine: 4.0
You can go to any auto parts store and rent one. It connect above your oil filter, Where you oil pressure switch is currently connected.
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