Jeep 4.0 question

zuksammy

New Member
Joined
Dec 2, 2008
Location
High Point
Hey guys I just bought me a 2000 xj with 155k on the clock. I was driving it around last night and my oil pressure went to zero. So luckily I was at my house. So I popped the hood and the oil pressure switch was broke. So I went this am and got one. Got it in then went for a drive it stays anywhere between 30-45 psi under a load then when I come to a stop 20-25 at idle. So my question is should I go ahead and replace the oil pump and the pickup I know they are bad about goin out? Also while I am in there I can change the rear main while I am in there correct? Cause you don't have to pull the trans do you? Also should I do anything or check anything else since it's my DD???


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that sounds perfectly fine to me. i put a high volume oil pump in my yj with 215k miles on the clock and it still idles at 30psi. under load it runs at around 50. me personally i would just change to 5w30 full syntetic and run the lucas oil stabilizer. its all i do in the yj and it works awesome. my rear main still leaked after a new one anyway but its barely anything now im running that combo. if your running those pressures right now then the pump is doing just fine
 
Ok cool guys I didn't know if I should replace or not. I will just keep a eye on it and if it starts to loose pressure I will replace it. I know these motors will last so I want to take care of it and have fun with the jeep.


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IF pressure readings are correct I see no need to replace the oil pump. Rear main isn't that hard to do, I'd go ahead and do that, I like em as leak free as possible.
 
JC said:
IF pressure readings are correct I see no need to replace the oil pump. Rear main isn't that hard to do, I'd go ahead and do that, I like em as leak free as possible.
Click to expand...

Ok well you can drop the pan and do it from there correct? Since it's a 2 peice seal


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zuksammy said:
Ok well you can drop the pan and do it from there correct? Since it's a 2 peice seal


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Click to expand...
yes you can do it that way, Just got done doing a rear main and pan gasket on a 4.0. the pan gasket annoyed me more than the rear main.
 
You've got 20psi at hot idle. It's fine. I wouldn't do a thing.
 
Yeah, I mean... somebody correct me if I'm wrong here. But I wouldn't worry about it until it was only making 5-10psi at hot idle... or the top end starting making noise. As long as there's oil flow, and a little bit of pressure up top, it should be okay. I don't think that motor has hydraulic chain tensioners or anything like that.

You can throw a gauge on there to keep an eye on things, but like I said... I wouldn't lose any sleep over it.
 
That oil pressure is fine, like Shawn said,at 5-10 I would worry.
A straight weight would be fine in the summer months but I don't reccomend it in the winter months. Anything with over a 100,000, I add a quart of Lucas in to the oil change.(my personal opinion).

*******In my personal vehicles, every other oil change, I use a quart of transmission fluid in place of a quart of oil, it helps keep things clean*******
 
Ok cool guys do y'all have a choice of oil weight wise around here for the fall and winter? I will run a bottle of Lucas in it each oil change I do.


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