Changed rear main seal...no oil pressure
Thread Starter
Seasoned Member
Joined: Nov 2010
Posts: 469
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From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
Title says it all...changed my rear seal and now have 0 oil pressure. All went smoothly. It came out easy and went in without fight. Replaced the pan gasket....changed oil filter...filled with 6qts of oil. Started her up and have no oil pressure. Anyone have this happen before? Im livid and baffled.
Thread Starter
Seasoned Member
Joined: Nov 2010
Posts: 469
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From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
Did you damage the sender unit when you replaced the oil filter? I would guess your pressure is fine but your gauge isn't working.
Did you do anything else while you had the pan dropped? Like clean the pickup screen or mess with the pump?
Greg
Did you do anything else while you had the pan dropped? Like clean the pickup screen or mess with the pump?
Greg
Thread Starter
Seasoned Member
Joined: Nov 2010
Posts: 469
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From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
The engine starts right up, makes no noises what so ever and doenst have any hessitation. Before all this RMS leaking I had a dry start up that sounded horrible. Now the engine is quiet as can be with no noises which leads me to think it is getting oil throught the block.
Ill check this at lunch if I go home. Thanks again for your advice.
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Junior Member
Joined: Jul 2011
Posts: 77
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From: Escondido, CA
Year: 1998
Model: Cherokee
Engine: 4.0L
Assuming its not just the wire connector come loose you can purchase the part from Rock Auto for $15-26 depending upon who the manufacturer is....
Look up the part under Electrical-Switch&Relay for your year XJ.
www.rockauto.com
Look up the part under Electrical-Switch&Relay for your year XJ.
www.rockauto.com
CF Veteran
Joined: Oct 2009
Posts: 2,867
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From: Fauquier County, Virginia
Year: 1991
Model: Cherokee
Engine: I-6 4.0 HO
Thanks for your input. This very well might be my problem. I didnt touch the screen or pump in fear of messing something else up that was working fine. I remember when I was removing the oil filter I heard a pop/crack noise. At the time, I was covered in grease and assumed it was the tool hitting the block. After your comment, I googled the oil pressure sending unit sensor and noticed its right behind my filter between the filter and the block. Im hoping this is the case.
The engine starts right up, makes no noises what so ever and doenst have any hessitation. Before all this RMS leaking I had a dry start up that sounded horrible. Now the engine is quiet as can be with no noises which leads me to think it is getting oil throught the block.
Ill check this at lunch if I go home. Thanks again for your advice.
The engine starts right up, makes no noises what so ever and doenst have any hessitation. Before all this RMS leaking I had a dry start up that sounded horrible. Now the engine is quiet as can be with no noises which leads me to think it is getting oil throught the block.
Ill check this at lunch if I go home. Thanks again for your advice.
Thread Starter
Seasoned Member
Joined: Nov 2010
Posts: 469
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From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
I have learned my lesson from autozone. I pretty much buy nothign there mechanical anymore. I will buy a felpro gasket from them or fluids....but any part I have bought from them never lasts more than 3 months. They offer "lifetime" warranty, but I get tired of changing out the same part every few weeks haha.
Im 90% sure its the sensor. I always loosen the filter from underneath and remove from up top, but last night i tried to loosen it from up top and that is when i heard the crack/pop sound.
On a side note...I used a fram filter (worst ever. Not even a true filter) and a Wicks and both caused severe dry starts with 2-3 seconds of no oil in the crankcase. After changing to a Mopar filter after researching online. The 3 times I started it last night and once today it was a fast, quiet, and smooth start.
Im 90% sure its the sensor. I always loosen the filter from underneath and remove from up top, but last night i tried to loosen it from up top and that is when i heard the crack/pop sound.
On a side note...I used a fram filter (worst ever. Not even a true filter) and a Wicks and both caused severe dry starts with 2-3 seconds of no oil in the crankcase. After changing to a Mopar filter after researching online. The 3 times I started it last night and once today it was a fast, quiet, and smooth start.
Thread Starter
Seasoned Member
Joined: Nov 2010
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From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
http://jeep-xj.info/HowtoRearMain.htm
Here is a tip. When removing the seal, it says use something like brass or hard plastic to not stracth/damage your crank. Well I tried a few things with no luck. I finally got a flat head screwdriver....carefully placed it on the seal and hit it 2 times with the palm of my hand. It came out like a charm. Also...I sprayed a lil bit of carb cleaner on it to help break away any gummy oil that was holding it in place. Again use the screw driver at your own risk....but if careful with it, it can be used
I also recommend you get the double seal not a single. I had never changed a RMS before and I didnt think it was hard at all. Just time consuming with the freakin 50 million bolts for the oil pan.
Here is a tip. When removing the seal, it says use something like brass or hard plastic to not stracth/damage your crank. Well I tried a few things with no luck. I finally got a flat head screwdriver....carefully placed it on the seal and hit it 2 times with the palm of my hand. It came out like a charm. Also...I sprayed a lil bit of carb cleaner on it to help break away any gummy oil that was holding it in place. Again use the screw driver at your own risk....but if careful with it, it can be used
I also recommend you get the double seal not a single. I had never changed a RMS before and I didnt think it was hard at all. Just time consuming with the freakin 50 million bolts for the oil pan.
hhaha yeah doesnt look bad. did ypu have to hang the axle? I have 6.5" rusty long arm lift, and wondering if I would need to even jack it up.
Which seal did you get, as in from which retailer. Did you use RTV or anaerobic sealer on the rear cap.
Which seal did you get, as in from which retailer. Did you use RTV or anaerobic sealer on the rear cap.
Thread Starter
Seasoned Member
Joined: Nov 2010
Posts: 469
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From: Spring, TX
Year: 1994
Model: Cherokee
Engine: 4.0
I didnt hang the axles or remove the tires. I have a 4.5" lift and it was enough room.
Felpro seal. Get it at any auto parts just about. Just ask for the double seal. I did use RTV on the top of the bottom seal where it meets the top and a tiny bit on the bearing cap.
Felpro seal. Get it at any auto parts just about. Just ask for the double seal. I did use RTV on the top of the bottom seal where it meets the top and a tiny bit on the bearing cap.


