4.0 oil pressure?? - Pirate4x4.Com : 4x4 and Off-Road Forum

theHenz33 · 06-29-2007, 05:52 PM

1989 cherokee with 4 litre. mechanical oil pressure gauge. after a 3-5 mile ride, come to an idle, oil pressure drops to practically 0. installed a new oil pump, and 20-50 oil, but still no change. could the engine have that much clearance?? engine has 146,000 miles and was previously well taken care of.
since pressure problem, engine is now just starting to have a slight tick.
any suggestions?

the Merg · 06-29-2007, 08:35 PM

your sensor is kaput. It's a pretty common failure, replace it and you should be fine.

XxStirCrazedxX · 06-30-2007, 01:24 AM

Correct me if im wrong, but a "mechanical oil pressure gauge" doesnt have a sensor. its a nylon tube (Most of the time) that runs from your engine to your gauge. Try doing a compression check on you engine and/or try a new gauge.

87manche · 06-30-2007, 06:18 AM

sounds to me like the motor is done.
only way to tell for sure is going to be drop the oil pan and look at the bearings.

jbrooks86 · 06-30-2007, 11:25 AM

Oil Pressure Sender for 89 xj w/ oil pressure guage, not light...\
Borg Warner Part # S-768.

By mechanical, I assume you mean that it has an oil pressure guage not light?

If so, I would try this first.

kaswanso · 11-06-2007, 07:48 AM

I have a 1990 Jeep Cherokee, I replaced the oil pump and rebuilt the lower end (turned crank and new rod and main bearings) I plastic gaped it and i still have 0 oil pressure at ideal when its worm. I have a mechanical and the electric gauge both say the same. As far as I know the only thing left to be replace is cam bearings, or could there be a crack in a oil passage or something. Any ideas?
Thanks,
Kris

hdcherokee · 11-06-2007, 03:37 PM

i have a 90 4.0 with about 175000 on it. its been sitting for about a year with some start up just to move but never let it warm up all the way. the other day i did a radiator and heater core on it and let it run till it go warm. At idle my gauge also sayes zero but you rev it up and oil pressure goes up. but before it was sitting it was fine that i can remember. i would think if it didnt have any oil presure you would hear it start knocking or ticking but i don't hear it. i am going to put a diffrent gauge on it and i will get back to the post,

my-xj-addiction · 11-06-2007, 03:46 PM

what kind of oil and filter do you use????

strck9 · 11-06-2007, 03:57 PM

for all you guys that think you have a problem, most likely you dont, chrysler spec on oil pressure at curb idle warmed up is only 3-5psi. dont worry about it until you have no pressure at higher rpms.

john0089 · 11-06-2007, 04:25 PM

as far as I can remember this has happened in almost all of the jeeps I have owned and driven......i have never had any major problems, I have learned to just ignore the oil gauge at idle

PureFunction · 11-07-2007, 07:06 PM

If you have a fram oil filter on it take it off and use Wix or something like that. That solved my pressure problem when the same thing happened to me. Fram filters are known for collapsing.

06-29-2007, 05:52 PM	#1 (permalink)
theHenz33 Registered User Join Date: Mar 2007 Member # 89070 Location: upstate NY Posts: 14	4.0 oil pressure?? 1989 cherokee with 4 litre. mechanical oil pressure gauge. after a 3-5 mile ride, come to an idle, oil pressure drops to practically 0. installed a new oil pump, and 20-50 oil, but still no change. could the engine have that much clearance?? engine has 146,000 miles and was previously well taken care of. since pressure problem, engine is now just starting to have a slight tick. any suggestions?

06-30-2007, 01:24 AM	#3 (permalink)
XxStirCrazedxX Registered User Join Date: Jan 2006 Member # 65289 Location: Medford Oregon Posts: 334	Correct me if im wrong, but a "mechanical oil pressure gauge" doesnt have a sensor. its a nylon tube (Most of the time) that runs from your engine to your gauge. Try doing a compression check on you engine and/or try a new gauge. __________________ [QUOTE=Sturgell;7838459]Hell yes it does. Going balls deep in some chicks bellybutton should be a requirement of all men.[/QUOTE] I'll stop Web Wheelin' when i get tires! post 46 in the biggest thread backfire of the year :flipoff2: [email]XxStirCrazedxX@Gmail.com[/email]

11-06-2007, 04:25 PM	#10 (permalink)
john0089 Registered User Join Date: Apr 2005 Member # 45561 Location: Charlotte NC Posts: 160	as far as I can remember this has happened in almost all of the jeeps I have owned and driven......i have never had any major problems, I have learned to just ignore the oil gauge at idle __________________ [FONT=Book Antiqua]1975 fj40 in progress[/FONT] [FONT=Book Antiqua]1968 fj40 in progress[/FONT] [FONT=Book Antiqua]2000 Jeep Xj DD[/FONT] [FONT=Book Antiqua]1996 Jeep Xj 8" Lift 35"s d44 d60[/FONT]

11-07-2007, 07:06 PM	#11 (permalink)
PureFunction Registered User Join Date: Sep 2005 Member # 53344 Location: Orleans NE Posts: 469	If you have a fram oil filter on it take it off and use Wix or something like that. That solved my pressure problem when the same thing happened to me. Fram filters are known for collapsing. Last edited by PureFunction; 11-09-2007 at 07:04 PM.

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06-29-2007, 08:35 PM	#2 (permalink)
the Merg Registered User Join Date: Jan 2007 Member # 85387 Location: Southern MD Posts: 492	your sensor is kaput. It's a pretty common failure, replace it and you should be fine.

06-30-2007, 06:18 AM	#4 (permalink)
87manche Registered User Join Date: Feb 2007 Member # 86724 Posts: 4,647	sounds to me like the motor is done. only way to tell for sure is going to be drop the oil pan and look at the bearings.

06-30-2007, 11:25 AM	#5 (permalink)
jbrooks86 Registered User Join Date: Nov 2000 Member # 2237 Location: Springfield, MO Posts: 292	Oil Pressure Sender for 89 xj w/ oil pressure guage, not light...\ Borg Warner Part # S-768. By mechanical, I assume you mean that it has an oil pressure guage not light? If so, I would try this first.

11-06-2007, 07:48 AM	#6 (permalink)
kaswanso Registered User Join Date: Nov 2007 Member # 102376 Posts: 1	I have a 1990 Jeep Cherokee, I replaced the oil pump and rebuilt the lower end (turned crank and new rod and main bearings) I plastic gaped it and i still have 0 oil pressure at ideal when its worm. I have a mechanical and the electric gauge both say the same. As far as I know the only thing left to be replace is cam bearings, or could there be a crack in a oil passage or something. Any ideas? Thanks, Kris

11-06-2007, 03:37 PM	#7 (permalink)
hdcherokee Registered User Join Date: Jun 2006 Member # 73797 Location: beachwood,nj Posts: 96	i have a 90 4.0 with about 175000 on it. its been sitting for about a year with some start up just to move but never let it warm up all the way. the other day i did a radiator and heater core on it and let it run till it go warm. At idle my gauge also sayes zero but you rev it up and oil pressure goes up. but before it was sitting it was fine that i can remember. i would think if it didnt have any oil presure you would hear it start knocking or ticking but i don't hear it. i am going to put a diffrent gauge on it and i will get back to the post,

11-06-2007, 03:46 PM	#8 (permalink)
my-xj-addiction Registered User Join Date: May 2005 Member # 47901 Location: Hampton VA Posts: 87	what kind of oil and filter do you use????

11-06-2007, 03:57 PM	#9 (permalink)
strck9 Registered User Join Date: Aug 2007 Member # 98734 Location: springfield, ma Posts: 6	for all you guys that think you have a problem, most likely you dont, chrysler spec on oil pressure at curb idle warmed up is only 3-5psi. dont worry about it until you have no pressure at higher rpms.