my 4.0 isnt getting oil to the top of the heads
11-19-2011, 02:37 AM
#1
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Year: 1998
Model: Cherokee
Engine: 4.0 6 CYL
my 4.0 isnt getting oil to the top of the heads
i just rebuilt my oil pump and re did the rear man and also flushed out the engine and still nothing (changed the oil and filter after each thing) any suggestions?
11-19-2011, 04:42 AM
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Year: 2001
Model: Cherokee
Engine: 4.0
pull the head and see if the clog is in the head or not, or just pull your oil pressure sending unit and see if oil starts coming out when you prime it or try to start it, if it does, pull the head find the clog and try to remove it, if it does not, your pump isn't pumping or your clog is in the bottom end and will need a rebuild. if you can't find the clog with the head pulled, gonna have to remove the remaining short block and (likely) rebuild.
Last edited by tavish_g; 11-19-2011 at 04:45 AM.
11-19-2011, 03:57 PM
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Year: 1998
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Engine: 4.0 6 CYL
k took off the valve cover and used an electric drill to turn the oil pump its getting oil but its moving really slow
11-19-2011, 06:33 PM
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Year: 1994
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Engine: flux capacitor
Could be cam bearings. What was you oil pressure like on the gauge with it running before you tore it down? Why did you year it down? Have you been losing coolant at all? Sounds like your losing pressure at the top, cam bearings are up there and usually the last thing lubricated. A leaky head gasket will kill bearins quicker than anything. Is the engine leaking? If so check your oil filter adapter, the o rings may be bad causing you to lose pressure. I had a head gadkey go on mine, no trace of water in the oil but was mysteriously losing coolant slowly until one day it started getting hot and the gasket finally popped. I put a remanned head on, rear main seal and since have had low oil pressure at idle. I'm going to pull the engine and install new main, rod and cam bearing here soon.
Last edited by knuckleduster271; 11-19-2011 at 06:43 PM.
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11-20-2011, 12:45 AM
#9
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Year: 1998
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Engine: 4.0 6 CYL
its not the filter adapter its not the head i just cleaned them put a brand new gasket on so i know its not that
11-20-2011, 04:35 PM
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11-20-2011, 06:36 PM
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Year: 1994
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Engine: flux capacitor
Kinda hard to give him advice with such little info. I started the smart *** remarks by asking him how many heads his 4.0 has lol. Cam is right below the head, bearings are what creates oil pressure, lose a cam bearing= no oil pressure coming past the lifters, push rods or into the head. Unless I'm missing something or if that opinion seems stupid somebody fill me in cuz I don't like looking like a dumbass 
I just can't see it being caused blockage unless he installed the head gasket upside down but then again he wasnt very descriptive. 
I just can't see it being caused blockage unless he installed the head gasket upside down but then again he wasnt very descriptive.
Last edited by knuckleduster271; 11-20-2011 at 06:56 PM.
11-22-2011, 06:17 PM
#13
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Year: 1998
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no i didnt say dumbass you added that but yea it must be the cam bearings then cuz that exactly what is happening
11-23-2011, 09:54 AM
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Year: 1994
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Did you take it apart because of the low oil pressure? What was the pressure reading at normal operating temp idle?
Last edited by knuckleduster271; 11-23-2011 at 09:58 AM.
11-24-2011, 01:59 AM
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Year: 1998
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it was normal up until a month ago thats when the pressure started to drop i didnt think anything of it at the time cuz there was no knock then came the knock thats when i redid the oil pump rear main and the pressure sending unit also flushed the system and still it had the same reading