Where's The Low Oil Pressure In A Jeep 4.0 Going? I Find Out!
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- Опубликовано: 27 авг 2024
- After an engine that I semi rebuilt was suffering from extremally low oil pressure. I change 4-5 different oil pumps in a different video just to see which would help. (link below) This time I set out to find exactly where its going and that I did. Hope this solves the mystery for you if you needed to know for your self.
Dex you remind me of a guy that taught me a lot about general mechanics… he was a farmer and learned by fixing stuff that broke by watching his Dad/Uncles fix stuff… you are a great reminder of how resourceful he was and I like to be. Keep it up.
Your not a hackjob at all. I would describe you as a common sense get 'er done 'er. The world needs more folks like you who aren't afraid to try new things and learn from experience.
Well put 👍
Best jeep channel on youtube hands down
Dex, I am convinced that you have solved the low oil pressure at idle issue. There are going to be a lot of engines out there getting new cam bearings, thanks to you. Great work and be safe.
Dex def got some good jeep content. Peace be
I’ve been fighting this same issue for years now with different 4.0’s after heavy abuse and I’m certain after watching your videos on this that cam bearings are the solution! You’ve done exactly what I wanted to try out to a T! Sounds like I’ll be doing cam bearings on my next one! Big thanks!
I really appreciate you taking the time doing this
To me thats one of the reasons i really like your channel
Really enjoy what ya doing
Dex, I’ve recently found your channel and I’ve got to say it’s my favorite RUclips channel of all time, plus, I’ve learned so much
Its like we are in the shop figuring it out together. Wonderful job Sir.
Thanks 👍learning myself!!
Appreciate the effort to get to the root of the problem 🤔that's how we learn 👍👍
This is what a mechanic 👨🔧 should be a problem solver fixing what needs to be fixed you are what I consider a real mechanic 👨🔧
I wish I could bring my 4.0 down to you so you’d rebuild it you do awesome work on these motors dex
Me too!!! I've got a 2002 YJ that needs his amazing hack-job-ed-ness - aka, mechanical genius.
At idle, only a few psi is ok....but you've come up with what finally looks like a great answer to this still unnerving "problem". Thanks.
Glad to help
I wish you were my neighbor, you stay in a good mood even when things are going bad, I usually get ticked & discouraged
DEX posted a short about traction. Full send VS Flat. Video Auto played before bed.
Next morning Chicago got hit with so much snow.
Then I remembered what DEX said.
Just kept it full send. Didn't get stuck once.
Dex out here taking one for the team, thanks brother xj all day!!!!
I'm glad somehow i bumped into your channel. Nothing but interesting good stuff.
Thank you for all the work once again. That new camera works great!
Dex out here teachin me more than school ever did! Thanks brother
That’s pretty nice. Lots of information and tips. Once it warms up I’m gonna use some of the knowledge I’ve learned from you on my yj.
Excellent! There's 1000s of this engines out there with the low oil pressure problem and finally I know what to do . thank you for making the video .
Uncle Tony’s garage brought me hear and I’ve enjoyed it
I’m really enjoying these videos, thanks for taking the time to get these out there.
My xj has identical oil pressure symptoms, gives me something to look for now.
I’ve got a 1999 XJ with 307,000 miles on it. The oil pressure has been slowly dropping over the last 50,000 miles or so.
I replaced the rear main seal at 250,000 miles and the rear main bearing looked brand new, so I had been presuming that the dropping oil pressure isn’t related to worn rod or main bearings. I was thinking it might be a worn oil pump, but after seeing this video it’s got me thinking worn cam bearings now.
I’ve still got 20 psi at hot idle and 50 psi when revved up so the oil pressure is good enough, but when it drops enough to start worrying about it and I yank the engine it’s definitely getting new cam bearings.
Thanks for the hard work to figure this issue out.
Yay!!!!! That was me who suggested the oil dye. I have a different account now, but it was pigtrapper2 when i wrote it.
Dex does appreciate comments and input. Tries to read all 👍👍👍
@janetbrowder6685 he commented that it was a good idea. Seems like a good dude. Definitely my favorite RUclipsr. I like cleetus McFarland but they kinda got away from their mechanic videos... which is what I like to watch.
Prove it.
Because it was actually ME who was pigtrapper2.
I was pigtrapper1 but everyone copied me I’m already wayyy past that pigtrapper69 now
Ignore the haters Dex and do what you do your doing good..
What a great video! This is without a doubt why my forgotten Cherokee had persistent low oil pressure issues. I chased that issue all the way up to the point you were at when you started this video. Thank you for solving this mystery!
Glad it helped! Put in some hard hours!!
I just want to say thank you. I have personally run into a few motors similar to this one. Some had the dreaded cracked head issue. Even after a new head, and new rod Bearings they still had low oil pressure just like this one. To me, you have just proven that cam Bearings really are the only way to fix this problem. I tried high pressure pumps as well, and it didn't make any difference. I had chatted with a few people that pointed to the cam Bearings being the problem, but you just proved it without a doubt. THANK YOU SO MUCH.
Glad to see the old, drill on oil pump trick helped you see that cam issue. Would have been tough to come to terms with the issue just by checking the timing chain. Nice job Dex 🤙
I like how your going though the trouble of this to figure it out. I don’t think your a hack job. Keep up the good work
It's very interesting. Hope you figured it out.
Great video Dex!
Man yeah that's awesome!
Dex, you are awesome ! ! !
Thank you for completing this series. I really enjoyed it. Shoot, I enjoy all your mechanic videos. Keep it up 👍
I love what you're doing. I wish that you'd been making videos years ago when I bought my first XJ. Could've taught me all that I needed to know before I had to learn it the hard way.
Also, yes, cam bearings are the #1 cause of low oil pressure at idle.
Well done ...🤙
Well well well - apparently Ol Dex has been hidein sompin - he has been “camshaft illiterate” the whole time - he said it had a bad johnsonator. No matter I just learned a lot about the 4.0 camshaft -
This is one of the most informative videos I’ve seen in a while. On any Chanel. It never occurred to me that you can have an oil leak inside the motor. This might be what’s wrong with my 4.2. It drops to 5-10 PSI when hot and idling. 160k miles on 89 YJ. Keep the videos coming.
I appreciate that!! Will do forsure
Another great video from dex
I started having oil pressue issues at about 260k. I also discovered my 0331 head was cracked at about 260k. The head was replaced with a rebuilt head at 280k and I tried changing the oil pump at 300k with not much improvement. I have been running 15w40 rotella for 55k miles with 20psi hot oil pressue. Previous to that my oil pressure would fall below 10psi and the light would come on. I know this is not a long term fix but if you want to eek out a bit more life from an engine needing cam bearings, before rebuilding, this has been working for me.
Always awesome videos
Brilliant. I've been working on AMC engines all of my life. The school of thought was generally "all bearings slightly worn" so throw in a high volume Melling if the hot low oil pressure issue arises. But I always suspected that it was a more specific area as the pressure swings while driving were so dramatic. If all the bearings are worn out, you'd end up with a lower overall loss in PSI, not up and down 20+ PSI with the throttle at any given temperature. Great work and I'll be pulling my cam bearings during the refresh this summer.
I saw the title of the video and went "yeah probably cam bearings" and I wasn't disappointed lol. Nice find.
Good video, nobody lied to ya
Your brother biting his tongue was cracking me up, he loves you very much. I have to say it's really awesome to see you experiment and see what happens sometimes. At least when you do something that's not by the book you're honest about it.
Now your camera work on the other hand leaves a lot to be desired 😂
Thank you so much for going to all that effort. I learned a lot. Your videos are great.
You're very welcome!
Nice detective work Dex!
I would love to see your brothers process, he has his way and thats ok, it may teach others a way that is better. 😊😊😊😊😊
Decks by Reading all these messages you've already helped tons of people out with the same issue.. This proves the time and effort you put in do this video. Was worth it keep up the good work .
Nice! I like that you didn’t give up
My dear friend Dexter, I feel like you are preaching straight to me brother man. Just did an engine swap to get our family xj going. Bout to make a 3 row xj. :) Went well, however I noticed that the motor I swapped in (244,000 miles 😅) has the issue you described of having low oil pressure once up to temp. I am about to replace the entire cooling system and the tires on it with income taxes, because i belive somewhere therin lies my hot running temp issue, which exasserbates the oil pressure. Oof wish me luck, as I buy another used cherokee to pull another motor and do a full engine rebuild on this engine otherwise. Money pits, gotta love em.
good job........ dont mention the haters, act as if they dont exist, praise the good commenters, grow your channel
Love your videos dex im learning alot about jeeps from you thanks
Next I mentioned this to you on a previous video in the comments I know about this. It happened to me and the Achilles Hill with these 4 row motors is the cam bearings. I've seen it on several videos on RUclips. Also, put heavy oil in it when you first started up. Let it break in after that change it to regular stuff. I use 10/40 when I fired up my engine. The first time I wanted to get the Heavy oil film to start and break in my cam. And everything else after that I change back over.
Nice work! I’m the type that has to stir over what caused the cam bearings to wear out. I’ve been bitten by cam bearing issues once. The problem became obvious after a few months of head scratching over it.
The right side of the motor is where the lifters and pushrods are, so it will read cooler on that side. Good job finding the bearing problem.
Just my own story and hope it helps the next guy.
In my case minimal oil pressure after a new 4.0L rebuild. Turned out to be the newly purchased China oil pump relief valve cracked open & stuck. No reason to replace the 260K mile OEM pump during my build as it worked fine just seemed new during a rebuild was the way to go.
Had to do another rebuild as defective pump with open releif valve finally burned my lifters, cam lobes, crank bearings, and push rod bearings from lack of pressure, all because I did not believe my oil pressure gauge.
Runs like a Champ now...lesson learned. If your going with a new China pump double check the relief valve is closed, not stuck open, and opens and closes properly. I'll reuse the China pump someday after honing out and polishing the relief valve bore. (Why even have a relief valve on a 4.0L oil pump?...sure there is an answer somewhere but I don't know.)
Big fan of common sense and down to earth mechanics. Also, I too pull heads with the intake and exhaust still attached...makes life easy during the re-install. I use dowl pins to guide the head back on as to not damage the new head gasket. I for one got burned on low cost head gaskets from local auto supply store, I only use MLS head gaskets now as added insurance.
Guess i need to pull the motor out of mine and have justin put cam bearings in it lol. Mains and rods looked great when I put it in but it has always had low oil pressure.
My dad and I put cam bearings into his 5.3 when I was like 17. Because of low oil pressure obviously after looking at all of the rod and main bearings which by the way looked perfect for 300,000+ miles. So one of the cam bearings actually spun out of the block. We replaced all of the bearings but the original cam went in hard and I’m not sure if the cam was warped or if the bearing tolerances where to tight. I saw a hagerty video not long ago showing to put cuts in the old cam to act as a drill bit if you know what I mean. Clean frequently and flush the oil passages and you’ll get a perfect running engine if you have cam bearing clearance issues. I forgot to mention the engine had good oil pressure for a little bit but lost it again because I think it spun another cam bearing
Yea thats common. Think of it as a reamer.
If cam bearings don't go in perfect they will be tight fit to the cam shaft journals.
Another great video!
Hope it many moons before my stroker has low oil pressure issues but this will definitely be checked first if I do! Thank you for everything you do best account on RUclips
You worry too much about comments. Take the good, ignore the rest. Even me if you want to.😉👍
I can relate. I bought a CJ7 with a rebuilt Jasper engine. Engine is 5 years old, but less than 10 k on it. It goes from 50psi down to 10 at operating temperature at idle. Off idle it goes up. No funny noise.
The footage with the new camera is real nice, it's a big difference
I have been wondering why the 4.0 has lifter noise and worn rockers and start making noise. The same ro kerarm and lifter design was in common use and problems were rare. You have actually revealed the root cause of several complaints that are common on this engine. My hat is off to you sir!
I just found your videos I think there cool, I’m a jeep Cherokee and 4.0l lover my self !
Welcome aboard!
Thank you for solving this issue.. alot of cam bearings will be sold tomorow...also ill be looking for this problem on the next 4.0 i get ahold of
I did cam bearings and mains and rods. Still didn't have oil pressure. Only thing I didn't change was the cam itself.
Main bearings and cam bearings are almost always the culprit in low oil pressure issues.
great info
F*ck the haters!! I enjoy watching your videos!!
Awesome video you worked your but off for this one
Yeah I did!
Thanks for doing the work to prove this out!
I dig your XJ content! Subbed
1989 4.0 with 179k miles has 35-40psi HOT oil pressure. Jumps to ~50 at a cold start and stays around 40 while driving. I'm so glad not to have this issue *knock on wood*, but it makes me wonder what really causes low oil pressure in a 4.0. It seems not to be related to mileage... has to be lack of a proper maintenance routine, right?
👍. Thanks for these videos!
I noticed you used oil dry. Aka diatomaceous earth for the oil spill. Highly recommend red clay. Aka Georgia clay. It’s way more absorbent than oil dry. And it’s free for us southern folk.
Have you ever tried to clean dried red clay from concrete?
Because oil dry leaves the concrete like new
It’s not hack job for the common man that doesn’t wanna spend 10 of thousands of dollars fixing his stuff your not a rich RUclipsr I can’t relate too your a relatable guy too just a guy trying too fix stuff in his shop and not spend a fortune appreciate your videos!
Great job. I have the same issues with a 01GC when hot at Idle the check gauges light comes on and there is 0 on the gauge I sit at a red light with it reved up some to keep oil pressure and my engine piston slaps bad also lol it needs a full rebuild, maybe someday
Wow thanks man
spec. oil clearance on a cam bearing is .001-.003. looks like someone mixed the up cam bearings on the original install for them to come out so easy. the insides of the bearings are the same the outside is different sizes for each journal, they have to go in order 1 through 4 . I'm not telling you I'm telling those who are watching who don't know and because you said the journals on the camshaft are different, they are not its the block that's different
Looks good Dex! Wish I knew what happened to the Comanche, even if you had to give up and move on. I just finished a 5.3L rebuild that went well.
Good job 👍
Dex, I was thinking about the black Comanche
I’m thinking the oil passages you show in this video are semi obstructed in the Comanche’s engine.
The oil flow is restricted in them so it has no where to go but lifters.
They pump up and the issue exposes itself.
That’s why it holds oil pressure like it does after it shuts down.
That oil takes a second to bleed off.
Well that seals the deal for me. My idle oil pressure will be 10 forever.
Mine is 10 at hot idle...I run the crap out of it. No knocking or tapping 😂. I've even seen it drop to 6-7.
Good video thanks for giving me something to watch and learn from.
Good job working it out 👍👍
The book says it will be only 13psi at 600rpm and 36psi at 1800rpm. Iv changed my oil pump twice. Cause i cant stand it being at 20 sitting at the light. Found a way to increase pressure up to 65 at start up and 25 at the light
I wonder if this testing will help with finding answers on the commache as its clearly some sorta oil pressure issue
Had same thoughts while watching this video. 👍👍
Good video!
So I’d definitely love to see a Dry Sump system down the road. Any hack way. Lol. I plan to run a Volvo electric power steering setup, and a BMW electric water pump. Putting a 4.2 crank and rods in a 4.0 and I want to experiment with freeing a 4.0 up as much as possible. Maybe smack a valve or something eventually who knows. 🤘🏼😁🇺🇸
Look up david Vizard.
He inspired me to shave weight off my crank, rods and pistons.
As well as lighten the flywheel.
Wow what a difference!!!
I think I took off like 6lbs off the rotating assembly.
It’s just a lil 1.9 diesel but spins up so much faster.
Starts and cranks faster.
Beautiful
Thanx dex great video
Brother, you need to replace that cam. It's wiped out on the journals. It will ruin new bearings. Great video.
that’s in a perfect world - you gonna live forever ?
@@rudybishop9089
Long enough to see the end of that engine.
I’ve had a dozen XJ 4.0’s, everyone of them will start cold and have 40+ psi on oil pressure. While driving it’s always good at idle it always drop.
I have one now with 221,000 miles and one with 120,000, great pressure at start up and while driving, at idle always around 10 psi. I can send videos of both if you’d like. I always just thought it didn’t need 40-50 psi at 800rpms.
I’d be interested in motor for future project what’s your price?
I have a jasper reman in mine with 20k miles. Sits at about 10psi hot idle. No knocking or tapping. Motor sat for 2-3 years in storage until I purchased it out of warranty. I'm just driving it...and I drive it hard.
99% of the LS engines i work on with low oil pressure is worn cam bearings. So its not a uncommon issue.
What’s the bottom $ for that engine?
I’ve been dealing with this problem for two years.
I want that motor!
Awesome!
Cool video. Did you happen to check if the crank or cam are warped, causing the uneven wear?
Maybe the cam bearings? Is it a leak, or low pressure? The cam is one of the failing areas in the 4.0. Surprised that you don't already know this given your vast experience with this motor.