Jeep 4.0 Low oil pressure

My jeep is messed up. ***FIXED** Gauge cluster was bad. Hooked up mechanical gauge, pressure was fine, so I replaced the sending unit, still read low, ended up being the gauge cluster and I had a spare cluster and swapped it out and its all good now.

Category:

Autos & Vehicles

Tags:

• Jeep
• Oil
• Pressure
• 4.0

[mike01166]

my engine is fine, its the actual gauge cluster that is broken. I installed a mechanic oil pressure gauge and my oil pressure is fine. And 4k for a new engine? Are you crazy? Ever hear of craigslist? Ive parted out jeeps and had trouble selling engines for 100 bucks. 100 bucks for a 4.0 is the going rate usually .

[mike01166]

My neighbor was a mechanic for the US postal service and worked on 1000s of XJ's. He said this is actually a pretty common occurrence. He told me there is a spring in a pressure release valve in the oil pickup that breaks quite frequently. Causes oil pressure to drop at idle. When I get back from my deployment and have more time im going to pull the oil pan and check it out.

[1993wrangler]

thats right check the oil pump also early 4.0 had rod problems that will cause low oil pressure your running about 10 psi at 210 the the spec is 12 psi at hot idle minimum so your not that far off just run it till it blows 4.0 are cheap

[mike01166]

i fixed the problem. it was the actual gauge cluster. I installed a mechanical gauge and my pressure is fine.

[mike01166]

still does it, im not gonna worry about it, the jeep was 1500 bucks, if it blows up, whatever, ill get a new 4.0 and toss it in there. Ive done oil changes, tried a heavier weight oil. My next plan of action is to pull the oil pan. I gotta check to see if anything is clogging the pickup. Someone said a gasket can disintegrate and clog it up.

[mike01166]

nah this aint my first rodeo. probably have done atleast 50 or so oil changes on jeep 4.0s, 100% not overfilled

[beretta1574]

I have the same problem in my xj, couple mechanical told me I have bad gauge coz the car sound normal !!

[pauladder]

yes defintly bad sending unit £80 for new one put in my self 10 min job fine now

[dropitlow305]

Does the oil pressure sending unit just register oil pressure? i broke mine accidently while replacing my oil filter and of course my gauge cluster is not registering oil pressure. is it ok to drive it like this for now? i understand i would have to fix it asap to get oil pressure readings. but does the sending unit actually play a role in helping the oil pump function properly? PLEASE HELP THANKS

[NoDutchGutsNoGlory]

ha! i dont have an oil pressure gauge on mine, just the "hey, you're fucked" light, but my fuel gauge jumps all over the place, i usually run out of gas at 1/4 tank. my gauges used to drop out alot until i cleaned all the connectors and contacts, but I even pulled out my transmission range sensor and cleaned it up because i would have to start it in neutral and on the highway it would drop into 3rd gear and throw a code, in my opinion, jeeps are electrical nightmares :-)

[Turizzle]

Aw shoot, I this irritating problem the oil pressure fluctuates with my tachometer accompanied with what seems to be the lifters tapping. its a 99 Grand Cherokee Laredo with 166k miles.. Any suggestions?

[97warlock]

I have a Renix 1988 4.0 in my Comanche and the oil pressure stays on 80+ ,Im gonna assume its a faulty gauge.

I just bought a set of SUN PRO gauges but it looks complicated hooking them up. Wish I could find a vid on how to do it.

[572blownhemi]

@1993wrangler is that the reason u own one?

[carlosxyz1981]

this video is quite old but I have been reading about low oil pressure, and it sometimes does not have a certain source, my jeep cherokee sometimes got down a line before the line in the middle, ( i hope you can understand) but a while after that it result in normal pressure, it is something random, I don't know

[PrincessKittenpants]

Are you sure it was the cluster and not just the sender? I'm on my girlfriend's youtube and she has a 2000 XJ with the same thing.

[roddyyy524]

check the oil pressure sending unit its like a $10 part our jeep did the same thing