No oil pressure?
07-16-2013, 09:21 PM
#1
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Year: 2001
Model: Cherokee
Engine: 4.0L
No oil pressure?
After warm up my oil pressure drops to "0". I have replaced the sensor. Any thoughts on any other causes, no including the oil pump going out?
07-16-2013, 09:45 PM
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Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Oil pumps don't make pressure, they create flow. When the flow is restricted, that is when pressure is made. Put a mechanical gauge where the sender screws into and see if it matches what you gauge on the dash was reading. Two causes of low oil pressure: the rod and main bearings are worn out, or there is a restriction at the oil pump pickup screen that is causing an oil starvation issue.
07-16-2013, 10:00 PM
#3
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Year: 2004
Model: Grand Cherokee
Engine: 2000 4.0
Also cam bearings,worn lifter bores and rare but possible bad block casting creating a breach (leak) in oil galley. Rod bearings have minimal affect on pressure. Mains,cam and lifter/bores have the greatest affect on pressure.
07-17-2013, 10:37 AM
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Year: 1986
Model: Comanche
Engine: 2.5L (2.46) AMC L4
what is the oil pressure when starting/ idling when cold? does the gauge flutter?
I just did my oil pump. fixed the 0 oil pressure problem.
and an oil pump DOES create pressure. why do you think as you accelerate or increase rpms oil pressure goes up. fuel PUMPS are rated by certain pressures, not certain rates of flow. yea, restriction to flow creates pressure... but where is the restriction??? in the oil pump.
thats what I believe , at least, and has worked for me. sometimes in the automotive/ mechanical world, there is no wrong answer
to the OP, what year and engine do you have? I have an 86 I4 2.5.
I just did my oil pump. fixed the 0 oil pressure problem.
and an oil pump DOES create pressure. why do you think as you accelerate or increase rpms oil pressure goes up. fuel PUMPS are rated by certain pressures, not certain rates of flow. yea, restriction to flow creates pressure... but where is the restriction??? in the oil pump.
thats what I believe , at least, and has worked for me. sometimes in the automotive/ mechanical world, there is no wrong answer
to the OP, what year and engine do you have? I have an 86 I4 2.5.
Last edited by AMCComanche2.5; 07-17-2013 at 10:40 AM.
07-17-2013, 10:59 AM
#6
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Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
what is the oil pressure when starting/ idling when cold? does the gauge flutter?
I just did my oil pump. fixed the 0 oil pressure problem.
and an oil pump DOES create pressure. why do you think as you accelerate or increase rpms oil pressure goes up. fuel PUMPS are rated by certain pressures, not certain rates of flow. yea, restriction to flow creates pressure... but where is the restriction??? in the oil pump.
thats what I believe , at least, and has worked for me. sometimes in the automotive/ mechanical world, there is no wrong answer
to the OP, what year and engine do you have? I have an 86 I4 2.5.
I just did my oil pump. fixed the 0 oil pressure problem.
and an oil pump DOES create pressure. why do you think as you accelerate or increase rpms oil pressure goes up. fuel PUMPS are rated by certain pressures, not certain rates of flow. yea, restriction to flow creates pressure... but where is the restriction??? in the oil pump.
thats what I believe , at least, and has worked for me. sometimes in the automotive/ mechanical world, there is no wrong answer
to the OP, what year and engine do you have? I have an 86 I4 2.5.
07-17-2013, 02:18 PM
#7
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Year: 1997
Engine: 4.0
oil pumps are wear parts as well. if replacing one increases pressure what's the issue?
and fwiw a friend replaced his rod bearings and oil pump after tearing down a 0 pressure motor. it now has 40 lb at idle. 220k mile motor.
and fwiw a friend replaced his rod bearings and oil pump after tearing down a 0 pressure motor. it now has 40 lb at idle. 220k mile motor.
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07-17-2013, 07:56 PM
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Year: 1990
Model: Cherokee
Engine: 4.0
what happened since yesterday? did you put a mech gauge on it like bustedback said? pull the pan and look at the screen? pull apart the motor and check bearing clearances? no info from your side like AMC asked either. help us = help you.
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