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-   -   2000 jeep grand cherokee no oil pressure when warm (http://www.jeepgarage.org/f203/2000-jeep-grand-cherokee-no-oil-pressure-when-warm-41412.html)

TIMJONES271 04-29-2012 06:55 AM

2000 jeep grand cherokee no oil pressure when warm
 
I just bought suv, at cold start engine has about 40 psi as engine warms psi drops to zero , i have changed oil pump, pressure sensor, put 20w50 in it changed filter, put mechanical pressure gauge on to confirm low pressure, everything looks clean when i had pan off, I STILL HAVE LOW OIL PRESSURE, TODAY I AM GOING TO TRY THE LUCAS OIL STABILIZER, any help would be greatly appreciated

2005JGC 04-29-2012 06:02 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
if this is the 4.0l I6 they have a problem with a cam bearing walking out of the journal thus causing low oil pressure. there is no repair for this other than replacing the block due to the oversized journal... not sure what a machine shop could do for you if this is the case.

TIMJONES271 04-30-2012 09:23 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
Thank you for responding, i wonder if you can see the cam bearings from underneath with the oil pan off, i noticed that i could see the cam when i changed the oil pump any maybe move them back in place

2005JGC 04-30-2012 11:42 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
I could not tell you for sure but I will tell you that they walk out because of the journal is machined too big, so pushing it back in wont do anything for you

TIMJONES271 05-12-2012 04:44 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
dropped the pan again today and looked at the cam bearings, i can see each one, they seem to all be in place, soooo to try to get the oil pressure up i replaced the pressure relief spring in the oil pump with a stiffer one, at first i tried 20w50 with one quart of lucas oil stabilizer, but after the engine reaches 180 degrees at idle the pressure drops low enough for check gages light to come on and alarm ding, i tried something thicker so i changed the oil to 85w140, but i still have the same problem, does anyone have any ideas for me to try next?

2005JGC 05-13-2012 02:51 AM

Does the engine knock? You may be looking at a failed main bearing if the motor is not especially noisy.

Sent from my SCH-I500 using Tapatalk 2

TIMJONES271 05-13-2012 06:54 AM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
Engine sounds find, no odd noises, except the dinging check gages light that comes on when i stop at stop sign or something and the oil pressure drops to zero

TIMJONES271 05-13-2012 06:18 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
Drove the jeep to my sons house about 20 miles away today, cold the pressure was 60 psi as it warmed up during the trip it steadyly dropped, at a red light 20 mins into the drive the pressure finally dropped enough to cause the check gages light to come on and ding, after an hour at a resturant we headed home psi was about 30 psi so i decided to take the interstate home, 5 minutes on the interstate at 65 mph the pressure held at about halfway between 10 and 20 psi, as some as i stopped on the exit ramp pressure droppped to zero i pulled over, checked everything , every thing was fine, no noises, engine running smooth, i drove the last 6 miles to home at around 55 mph the oil pressure never raised above zero, when i got home i put the mechanical gauge back on, it also states zero oil pressure, i could see the oil in the oil line to the gauge, it wasn't moving, i revved the engine alittle and i could see the oil move slightly, but still zero pressure, still no engine noise, i removed the filler cap and looked inside, i could not see much, but i did not see oil splashing around but that does not mean anything like i said i could not see much, and i did not hear any lifter noises, or rockers tapping, everything seems to be running smooth and quite, so i thought maybe the port for the sending unit maybe blocked, so i removed the oil line and blew 150 psi of compressed air through the port, i put the mechanical gauge back on and no change zero pressure.
Does anyone know if there is another port that i could try the pressure gauge on????

bigdee 05-13-2012 09:04 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
Wow, I have the same problem. It was like this when I bought the Jeep six months ago.....I finally said to heck with it and just drive it. However mine does come up to about 20 psi at cruising speed. I can see oil circulating through the oil fill cap but it is very little unless I rev it above idle. I do plan on dropping the pan to look at the mains and cam. A bad main makes the most logical sense because there would not be any noise with just ONE bad main.

TIMJONES271 05-14-2012 05:47 AM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
I thought about the bearings but there is no metal shavings in the bottom of the oil pan indicating bearing wear

amw5 05-14-2012 07:41 AM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
What kind of oil filter are you using? If it's a Fram, change it out and put in a quality Mopar, Mobil, or Pure One filter, for the filter may not be allowing pressure to build up (drain back valve issue).

TIMJONES271 05-14-2012 05:14 PM

Re: 2000 jeep grand cherokee no oil pressure when warm
 
Ok thanks i will try that today!


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