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Unread 03-08-2013, 09:35 AM   #1
mudnmore
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Low oil pressure. Rough idle

Hey guys. I'm brand new to this forum but would like any help I can get. A few weeks ago I took my 2000 jeep cherokee sport with a 4.0 engine in to have a motor blower resistor replaced I also had 4 brand new sensa trak shocks installed. A day or two later I noticed a massive coolant leak where I would lose all the coolant in my reservoir tank within 30 mins of driving. I wen to a different shop and replaced the radiator, water pump, thermostat, and valve cover gasket because I had an oil leak. I just got my Jeep back two days ago. Yesterday I had parked at a store and went to start it and it idled extremely rough and stalled within 2 seconds. I started it again and it still idled rough and I noticed the oil pressure had dropped very low from what it usually is. It's usually around 50 at idle when cold and maybe 45 when warm but it had dropped to about 20 and only increased when I gave gas. The engine was warm already. I drove it some more and it was still rough and had low oil pressure around 30. Sorry for the long post. Oh, and I still leak coolant. It puddles on the ground in the very front of driver side headlight. Any advise would be extreamly appreciated. Thanks everyone.

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Unread 03-08-2013, 09:39 AM   #2
bobthecatkiller
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Well at least you have a actual coolant leak...

Edit: ok sorry I was in the middle of a quiz lol, what up with your mechanic? If you took it there to get your leak fixed and it still leaks, thats a problem.
check your oil and coolant for a milkshake like mixture, although 0331 head cracks are less common then the Internet makes them seem you can't rule out the possibility. The #1 symptom of the 0331 head crack is mysterious coolant loss, so its kind of good you have a actual leak you can see... Although a cracked head would explain your oil pressure I doubt it, its more likely the oil pressure sending unit is bad.
Have you checked the coolant bottle for cracks?
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Unread 03-08-2013, 10:55 AM   #3
mudnmore
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Coolant bottle seems fine dont notice any cracks. I dont have a mechanic that I can go to that I like. One place did the shocks/ motor blower but the were way to expensive. A different place did the rad, stat, VC gasket, and water pump. I purchased all the parts myself and asked if he could install them. I would think if it was a hose or something he would have noticed. I cant seem to find a decent and honest mechanic for my life. I was thinking maybe the sending unit. I just dont understand how I can something simple done and now I have all these repairs all of a sudden.
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Unread 03-08-2013, 11:02 AM   #4
bobthecatkiller
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Unread 03-08-2013, 11:15 AM   #5
buildin1XJ
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Leaking under the driver side head light would indicate a lower radiator hose leak probably where the hose attaches to the radiator make sure the hose clamp is tight. Also make sure the hose coming from the coolant reservoir is firmly attached to the radiator and that the rad cap is not leaking.
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Unread 03-08-2013, 11:23 AM   #6
AGDubyaJ
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oil pump pickup screen could be clogged up/ bad oil pump, could be the sending unit, could be you overheated and wore out bearing, seals, etc. best bet would be to run a mech. gauge on your sender and see what your pressure is really at. if its actually reading low, drop the pan and replace your pump, its cheap and easy.
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Unread 03-08-2013, 11:32 AM   #7
buildin1XJ
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I agree with a mechanical oil pressure test and getting your known coolant leak repaired. The last thing you want to do is overheat your 2000 XJ.
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Unread 03-11-2013, 12:41 PM   #8
mudnmore
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UPDATE


I used a mechanical gauge yesterday and numbers were accurate and where they should be. Also coolant leak magically stopped. Havent lost any coolant from the reserve tank either. Only problem is my idleing stills seems slightly rough to me and my gauge still reads about 20-25 psi when engine has been and is hot at idle. It is starting to warm up and turn into spring weather so I think I will do an oil change using 10w30. The jeep has 126,000 miles but the engine only has about 65 or 70 thousand roughly. I was considering switching to synthetic. Is this a good idea?
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Unread 03-11-2013, 12:48 PM   #9
Tru2Chevy
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Nothing wrong with switching to a good synthetic. I run Pennzoil Platinum in most of my vehicles, many other brands are also good. If you don't already, switch to an oversize filter too (a quick search here will bring up part numbers for all of the popular brands of oversize filters).

If your gauge is still reading low, but a mechanical gauge is showing your oil pressure at normal levels, you should start by replacing your sender.

How long has it been since you have done a full tune up?

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Unread 03-11-2013, 12:57 PM   #10
mudnmore
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I was thinking about replacing the sender but doubt that causes the slightly rough idle. As for tune up I just put new plugs in about 2 weeks ago and air filter about 8 months ago. I have a new air filter that I will put in this spring. I always do oil change every 3 to 4 thousand miles.
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Unread 03-11-2013, 01:05 PM   #11
Tru2Chevy
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Yea, the sender shouldn't affect your idle, but it's always good to know what your correct oil pressure is.

Did the rough idle start around the time you did the plugs? What plugs did you use? Have you checked to make sure that all plug wires are seated correctly on the plugs and coils?

- Justin
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1996 Cherokee Classic - 3.5" lift / 31.0x10.5 Mastercraft Courser CTs / Warn XD9000i - Stripped for parts / junked :(

2004 Grand Cherokee Laredo - 4.7, bone stock - Wife's DD

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Unread 03-11-2013, 01:26 PM   #12
mudnmore
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I used mopar champion plugs. I had my radiator, water pump, valvecover gasket and thermostat all replaced about 50 miles after I had installed the plugs which is when I noticed the oil pressure/rough idle. I did not unbold and check the plugs. I made sure the wires were on very well before I was done so I didnt think that was an issue.
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Unread 03-12-2013, 07:23 PM   #13
mudnmore
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Yet another update.

So I have done alot of research. After searching I might have a heat soak issue. Although I really am not positive. With that im not sure what I should do from here. I got rotella t5 10w30 sythetic blend with a mopar filter and want to see if that helps my pressure problem but doubt it will help with the idle. It only idles rough after engine has warmed up, I turn it off, and start it again after a few minutes. I really just dont know.
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Unread 03-13-2013, 03:30 PM   #14
buildin1XJ
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Quote:
Originally Posted by mudnmore View Post
Yet another update.

So I have done alot of research. After searching I might have a heat soak issue. Although I really am not positive. With that im not sure what I should do from here. I got rotella t5 10w30 sythetic blend with a mopar filter and want to see if that helps my pressure problem but doubt it will help with the idle. It only idles rough after engine has warmed up, I turn it off, and start it again after a few minutes. I really just dont know.
That is a common symptom of heat soak which is a known problem for a 2000 model.
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