jeep cherokee xj 4.0 no oil pressure at idle when hot

[@chrisgodinez2568]

Hey guys I have owned three jeeps with the 4.0. One of them had no problem with low oil pressure because it was in great condition compared to the other two. The other two I did replace the oil pump but while you have the oil pan off replace the rod bearings. That will help with the situation immensely. Unfortunately somebody in the life of the vehicle did not change the oil and this is the reason for this situation. Make sure you change your oil on time.

[@harvestblades]

And a hot engine flush may help, but more likely will breakup sludge after the flush, & clog pickup or oil galleries.

[@erwinpadgett1050]

Rod bearings don't hold the oil pressure. It's cam bearings that keep your oil pressure up.

[@74TugBoat]

I'm having the same issue with an 01 wj 4.0 196k. Previous owners neglected it of oil changes and had lots of sludge buildup.. Replaced the cylinder head, rockers, pushrods and lifters, gaskets, new heater core and water pump and thermostat. Did not remove timing cover whatsoever. New oil pump and sensor. Thoroughly cleaned oil pan and valve cover in a parts washer at my workplace. Did my best to clean galleys to sensor and to pump as well. Confirmed sensor works properly by swapping the sensor with the one in my lifted 4.0 that has 40+psi of oil pressure. Both sensors read the same in both vehicles. Have put two oil pumps in it thinking the high volume one was faulty. Running into exact same issue. Pulled rod and main bearings off and they look brand new. Cylinders still show cross hatching. Have done 2 oil flushes and 3 oil changes and driven a total of 200-300 miles since first startup. Weird thing is there is almost no ticking or knocking sounds like the cleanest running 4.0 I've heard that wasn't just built at a shop. Started to assume cam bearings. Noticed a decent amount of wear on the cam lobes themselves also. Any help or advise is appreciated!

[@317scott]

replace the main and rod bearings you can do this with the engine still in the jeep. im not a mechanic and i did it. remove the oil pan to gain access to the bearings normal oil pressuer for over a year for me with no issues

[@krwiles]

Just got a new 4.0L motor from Eagle and it does the exact same thing as the old worn out core 4.0L with 395,000 miles on it. Cold start oil pressure for old and new motor were very similar around 40+ PSI give or take. Operating temp for both motors were very similar with a cold old winter and heater on OPTEMP 180, idling unshaded for an hour during a vietnam summer in Florida the AC dumping every BTU of heat into the engine bay as possible it gets close to 210/220. Once warm my oil pressure is virtually the same as yours

[@nj1639]

Same issue here, 2001 Sport. Zero oil pressure when hot. The other day I removed the oil filter adapter and plumbed it straight to the block using the 1" nut and threaded hollow bolt in the adapters configuration. 40psi when running, 20 when hot and idling. We'll see how it goes. WIX 51348 or it's equivalent. It was a bear to crack that torx bolt loose.....

[@brandenhall1617]

Cam Bearings my 01 Cherokee has same problem. Not much you can do if it’s that at least nothing cheap

[@mikeylikes21p79]

I have a 2000 jeep wrangler and my oil pressure drops when reaching normal temp. I've replaced the oil sensor with no change. Today, I tested it with a pressure gauge and it was going to almost zero pressure when reaching normal temp. So I'm going to try and clean out the hole where the oil temp sensor goes and if that doesn't work I'm going to use a thicker oil before doing any major work on the engine because other than that it's driving nice with no knocking or lifter noise. Hopefully this works!

[@TelecasterRon]

put a real oil pressure gauge on it. These other gages are garbage. Notice if you hear valve or lifter noise. Jeeps 232 258 4.0 don't have high oil pressure. It it is at 12 lb. idle and under 35 at 45 consider Main Bearings. Beware on CJ's to look on the boss at the oil filter for any stamped info. Don't assume the bearings are standard and mic and check with platigauge. on a dry journal. should be 1to2 1000 clearance typically. Cam bearing require head removal. Have it reworked while off. Replace cam and lifters if worn badly. Note the valves if wornr afe not adjustable much. so pay attention to gasket thickness for the head. If cam lobes ard not worn and lifter are not worn thats fine. Be sure to put the lifter and push rods back in the exact order the were upon removal it you can reuse em. I think number 3 main is the thrust bearing. If done in jeep make sure the oil holes align with the bearings. The rear main while loose needs the top half of the rear main seal pushed out this is no easy task loosen the mains a little to release some pressure on the upper rear main seal. Do Not drive a hard metal too to drive seal around. I have made a copper wire puller and a flexible drive tool to aid in removal oil the new one Beware cuttng the length of the rear seal. Front seal just drives in the Timing chain cover housing. Lifter and head need removal to replace cam and bearings. Check oil pump. Try 10w40 never use quaker state or you will get tons of carbon inside the block. If the oil pressure is 15 and no knocks or clicks at warmed up idle it is fine. Do Not Use Thick Oil Addatives. They will raise oil pressure at the gauge as your bearings burn up. heavy oil is not a solution. 10 40 should be it. I ran CJ 5 232 n 258 for over 250k and never had any issues.

[@ajkemer]

I figure you can do them without pulling the head same way people do cummins cams using wooden dowels

[@JPG2105]

Go with 15w40 rottela Oil filter replacement Fixed this point im my 2004 Laredo 4.0

[@funnyfunnygirlie]

Having the same problem with my 2006 Jeep Wrangler.... after engine is heated and then comes to idle, pressure drops and the engine almost dies. Had the sending unit replaced and still having the same issue. Is there any resolve???

[@mattneubacher8261]

So ive done research and have seen that the oil galley that runs to the oil pressure switch gets clogged over time and after engine gets hot it will force the sludge to the sensor and get a false reading, take oil pressure sensor off and run a barrel cleaning brush down it a couple times i bet when you reinstalled the sensor and start it you will have great oil pressure at full temp idle

[@mitchelldelaleurs3295]

This piece your talking about, is it the same spot that he did or somewhere else

[@catalyst9317]

But many of us are having temperature gauge showing overheating right after engine pressure drops. That implies it's not just a sensor issue, but a legitimate mechanical issue.

[@tyrantroll7281]

I just got an 03 myself. I have noticed if I shut the vehicle off and turn it back on the pressure stabilizes. If I'm going down the road I throw it in Neutral and do the same thing ( this is not safe and don't recommend anyone doing it). This only happens when the engine is up to temp. This problem is kind of inconsistent, because I have gone miles to only yards before the pressure drops again. And repeat...

[@tyrantroll7281]

I'm hoping we can all narrow it down. I'm thinking something electrical but I'm no mechanic so I really don't know

[@sarahdluge9288]

Mine does the Exact same thing! Did u fix it !?????? Mine has high miles 3xx,xxx and I'm scared it's the bearings.

[@johnwigren2497]

Change oil filter..The Mobil 1 oil filter has a heavier spring that can cause oil pressure to go down.

[@keithkerr7321]

The oil is losing pressure between the crankshaft and bearings. The crankshaft needs regrinding and new main bearings fitted.

[@catalyst9317]

What would have caused this?

[@jeffreykropp7664]

Maybe replace electrical connector pigtail? I am dealing with same situation…..

[@joescrewdriver9000]

Main bearings are worn on the crank shaft. Possible considering that’s where you get majority of your oil pressure. Also I think that would coincide with piston rings. Like fixing a plumbing problem with multiple leaks each one you fix creates more pressure back in the lines.

[@michaeldistad8146]

I have been running into bad oil filters where the oil filters actually collapse on the inside I have replaced three oil filters set word collapse different brand name change your oil filter and see if that makes a difference

[@JustinFisher-q5g]

I feel your pain I'm having the same problem on a brand new rebuild on 3500 miles. 2000 jeep Cherokee

[@JustinFisher-q5g]

In the summer I run 20/ 50 don't run it in the winter

[@JoshuaWBledsoe]

Literally my issue. Brand new rebuild less than 1k miles and had it built at a shop.

[@JoshuaWBledsoe]

Stroked and new cam, crank shaft and everything. Seems like there’s oil pressure though bc if not itd sound like shit id imagine. No idea what it is. New oil pressure sensor twice, changed the oil nothing obvious.

[@JustinFisher-q5g]

I was told that the oil pump will cause this problem. My luck I will get a bad one. When it's hot look down the valve cover we're you put oil in. and see if it is pumping oil out of lifter tubes . If it is not pumping oil to the lifters shut it down you will burn your engine up. Good luck Jeepster

[@JustinFisher-q5g]

I finally got a new oil pump haven't put it in yet. The old one had a lot of metal shavings. . When I get done I will let you all no if it fixed the problem

[@makingaZJ]

If you put a new oil pump in it & it helped but didn’t cure the low OP that’s almost a dead giveaway that your main / rod clearances are worn. I know it’s hard to believe with less than 150k but all it takes is seconds without oil to cause bearing wear.. it’s a shame but the truth. For an experiment I just assembled a 4.0 with main and rod bearings that I knew were out of spec (cam bearings were brand new) and sure enough they all have this issue. KZbin “mechanics” will tell you it’s timing chain noise or a bad oil pump but it’s all bottom end. The 4.0, 4.2 & 2.5 are all very simple engines. They’ll run forever until you starve them from oil or water.

[@DrHavok1]

Exactly

[@marioluigi6024]

I can confirm, mine is at 100k miles, even, and my bearings are completely destroyed.

[@TristanSogge]

Is it hard to replace them?

[@joshmarauder]

How much is a job like this cost to replace the rod bearings?

[@BUKWulfSh0t]

Hey, I have a problem with my 97 xj after driving it for about 30-45 minutes my oil light comes on whenever I come to a complete stop. The light turns off once i start driving and shift into 2nd gear.. but eventually comes back on when stopping. Any help is appreciated, thanks

[@joshuahaas5734]

Having the same issue with my 98 xj rn, did u ever figure out the issue?

[@BUKWulfSh0t]

@@joshuahaas5734 its low oil pressure

[@marseatay]

I’m having the same problem with my 01 Cherokee sport. The mechanic keeps telling me it’s the sensor. So I put a new sensor on and then another. I’m on my 4th one now. At idle it’s showing 1lb. of pressure, at 60 mph it’s showing 20lbs. I will admit, each time I get a new sensor it shows a different reading. My mechanic blames aftermarket parts. I’ll probably go now and get a new sensor and try again (they’re lifetime warranty). If that doesn’t work, I’ll go back to the mechanic and show him all these videos and comments. By the way, I have 217000 miles on it.

[@marseatay]

Well I put a new sensor on again, and now it’s reading great ! And now I just had a busted radiator, so being where I was having a new one put in I went ahead and replaced the water pump and thermostat,.. back to running great again !

[@mitchelldelaleurs3295]

@@marseatay so it seems that multiple sensors can be bad, and you just have to get really lucky to get a good one?

[@gabrielvidales6248]

What brand sensor did you get? My oil pressure is 10 at idle but normal when driving.

[@jan3019]

mine if the temp was below 210 it's good and when it reaches 210 the oil pressure goes down and it goes up to 20psi only when riding.

[@electrickrypt]

Experiencing the same problems with my 2001 Grand Cherokee Laredo 4.0L. Please provide any updates. Imma die...

[@bradyfox6777]

E Kryption I have the exact same Jeep but a 2000 with the exact same problem

[@johnwigren2497]

Same here.👍 I have a 2000 Jeep Grand Cherokee Laredo.. I did an oil change and the oil pressure is fine when I'm driving on the freeway.. it's over 40 but when I'm at a stop it's down to the 20 mark. It has 285,000 I'm just going to drive the damn Jeep down to the ground

[@marioluigi6024]

My 2002 Grand Cherokee, with only 100k miles, had this problem. Dropped the pan to change the oil sending unit, and found out that my rod bearings are completely destroyed.

[@ajmasson]

Did you figure this out? My 1998 XJ does the same thing! Sitting at a red light oil pressure will drop to around 20psi, if I am driving and moving it holds 40-75psi

[@rynob937]

If 20psi is the lowest it goes that is normal. I think normal psi at idle when hot is around 13-20

[@jamesfaison9410]

@@rynob937, exactly. The rule of thumb is 10 psi of oil pressure per 1,000 rpm. 20 psi is perfectly normal at idle

[@war42691]

That is exactly what is going on in my jeep. Thank you all

[@johnwigren2497]

Hey guys me too.. I have a 2000 Jeep Grand Cherokee Laredo 4.0 and when I'm at a dead stop idling it drops down to 20.. so I guess my Jeep has normal blood pressure. Thanks Guys!😃👍

[@anrhonyhafford1427]

Man I don't know how to message people through this but I'm having the same issue I replace my oil pump and the sensor and I'm still getting the same thing let me know if you found a solution

[@deniedjoo]

Put a gauge on it your pressure at idle should be around 13psi and 37-75 psi at over 1600 rpm. valve cover leak? My 98 xj has a similar issue but the psi is correct so I don't care

[@gabrielvidales6248]

So 13 is normal at idle? I’m a new xj owner and never seen oil pressure that low.

[@deniedjoo]

@@gabrielvidales6248 according to the book aka the people that built them 13 is acceptable but rare in the 17 years i have worked on and owned without a major failure all have been over 35 ibs idle

[@gabrielvidales6248]

@@deniedjoo Well it sits on the first line for oil pressure and sometimes rises above 40/50 when driving but, I don’t have lights on the dash so I’m guessing I’ll keep it pushing for the time being lol. I’ll definitely be weary about it.

[@deniedjoo]

@@gabrielvidales6248 u may need a sending unit have a mechanic look at it

[@robgee5219]

My jeep has the same problem I have rebuilt top of the motor new lifters and rods and oil pump on the bottom. still same problem all I can say is computer glitch cause if it were a bearing problem it would be constant loss of oil pressure. Not intermittent. Or possibly faulty oil pressure guage

[@redneckswitwheels]

Cam bearin...

[@markgabello58]

I feel for you yeah well maybe the crank seals are gone or you're losing pressure there real rear main seal be of any leaks how about with a can of some sort of seals in that motor

[@billhenfey3769]

My 98 XJ has the same issue. Any help or update would be greatly appreciate.

[@rynob937]

Next good will be the main bearings. This makes sense cause it needed a had gasket and coolant in the oil makes bearings go bad.

[@blurglide]

So what wound up being the problem?

[@alscompleteoutdoor9091]

Anyone put a mech gauge for oil pressure?...i just have the stupid L and H cluster...dont have issues with presssure until i get to change time and its just slow building it and causes it to stumble...im just curious what the pressure is

[@riverbumzz9960]

Did u reset the ecu?

[@rafaeltorres2886]

run thicker oil to see if it helps.

[@redneckswitwheels]

This isn't how u fix the issue. Running thicker oil will cause more oil starvation when the oil is cold...think son think...

[@Dieselpwr]

Yes thicker oil does fix the issue you can run it another 100k that way

[@adamsharp5593]

What is the part to the right with the plug and two screw heads ?? Mine on my 04 Grand Cherokee is clicking can anybody tell me why or what that is

[@teolewis8787]

I know it has something to do with the ignition. Because on my 94YJ the distributor comes out of that hole

[@davepenprase]

My thing is wtf isn't jeep telling us wtf is wrong??!! Maybe their computer is down. Jeep = just empty every pocket

[@Trebuer22]

Just here waiting for the update. Found metal shavings on my dipstick and am now worried about oil pressure

[@rynob937]

I have made an update video. And if you are finding sized metal shavings and your oil looks like it's filled with glitter it's time for either a rebuild or a new motor

[@Trebuer22]

@@rynob937 it's been like this forever, only has 150000 miles on it

[@pork3d]

@@Trebuer22 Metal shavings like described are signs of worn bearings. The metal is from the bearings moving or grinding against other metal. 150k miles seems to be the magic number I have seen a lot for worn bearings. A thicker oil can help but does not solve the issue just puts a temporary bandaid on it and if you wait too long you could have further issues with rods or the crank. Always a good idea to ask a local mechanic who has experience with the engine.

[@marioluigi6024]

@@pork3d Mine is right at 100k miles and my bearings are destroyed.

[@sthue1001]

Also, put a new sending unit in mine. Did not help. I have 190k. My engine is probably worn out from what I have read.

[@thomasdearment3214]

my 92 did that and my 01 does it too its a jeep 4.0 L thing

[@rayscopes]

Any update? Same problem here.

[@rynob937]

Unfortunately no. Recently I have been trying the cheapest options, next is new main bearings. I will make an update when I get it fixed.

[@sidepocketlouie590]

Same problem n can't figure it out... any update

[@rynob937]

Yes I have already posted an update video

[@danhambrick6331]

10-w30 is what you are supposed to be running in the 4.0L....

[@rynob937]

No it's 5w 30, says it on the fill cap and in the manual, but they are pretty much the same

[@bricebabcock7156]

Neither of you are really right. The manual recommends 5w30 in cold conditions and 10w30 in warm conditions.

[@critterwheelock4534]

Clean all your engine grounds problem should solve it self for the cost of a wire brush or some sandpaper

[@davepenprase]

And what do you base this assumption on?

[@Dieselpwr]

20w50 drive it till it knocks

[@sanya916]

Same issue

[@rynob937]

I just posted an update video of how I solved this problem, go check it out

[@jloco1980]

Change Oil pump bro

[@josephdepeyster5977]

Try sending unit

[@matthewotto9793]

Thats what he's doing in the video...

[@RockpileRanter]

did you even watch the video. you fucktard?

[@franciscorosales371]

Oil pump ...!

[@stevenrais9360]

Did you even watch the video. He tried that