Jeep 4.0 Liter Engine Issue: What You Need To Know

Everyone one always suspects the Jeep 4.0 liter noise to be a rod bearing due to age or miles but it most of the time is a busted/cracked piston. I show through the process of fixing this jeeps engine what to look for.

[@mojomello1249]

Buddy… you saved my fkn ass with this video. Long story long, my original engine started knocking last year, so I pulled the pan and found piston pieces. My solution was to just swap in a used engine with lower miles, thinking I’d be good for 100k miles at least. Well, after 12k, it started knocking. So I did this instead of another engine swap, and man that things runs smooth. Thank you Dex. I did the whole job for about $600

[@mojomello1249]

Oh, and if you ship parts to Florida, I would like to buy from you.

[@SuperUnknown1967]

For those of us that own, work on, and appreciate Cherokees, I thank you for your content! Especially the technical stuff. The presentation is perfect, you don't try to be a "character", just honest, open and straightforward. With your inventory and facilities, you have unlimited content. My only ask would be for longer videos. Keep up the good work Dex!

[@dexjs]

I appreciate that! I worry these are AI created comments but I hear so so many. I ain’t going away. I do think I will improve but never going fancy editing I doubt. Thank you!!

[@SuperUnknown1967]

No AI here - I own a '93 & a '97 xj . Merry Christmas from Saskatchewan, Canada​@justdexit

[@tomsmith2361]

Not A I either 😊. Ran a 93 XJ for 26 years. Bought a 2001 XJ in 2019🎉😊. Stay well

[@bryanmercado8755]

@@dexjsI think the editing is good. Not too raw, doesn’t feel “homemade” but it’s not overly edited. All the info is presented nicely

[@brucedragich1316]

I'm in NC, you seem like a busy fella , I am somewhat of a jeep enthusiast I have 3 xj's one for parts and 2 cj's one for parts , I have 2 4..2 motors , I'm thinking I have everything I need for a stroker, it's just a shame because both the 4.2's run like a scalded ape , did tge nutter bypass lighter dizzy curve spring and took 18k volt AMC ignition and put on so.e fomoco parts for inline 300, tbi era so coil is 40k volts , but love you content , think ima make a trip out Tennessee way once I've got my ducks in a row, you living the dream dude , if you live what you do , you never work a day in your life

[@williamsantuzzi5808]

my wife had the EXACT same issue with her 4.0 wrangler unlimited and ironically the same no.5 piston. i stood over her shoulder and guided her in the teardown and rebuild and she did all the work. the piston skirt broke at 211,000 miles and since she did the rebuild, she now has 270,000 and still running perfect.

[@FD-dh2fu]

Amazing. How much does a job like that cost? Thx

[@memorymode4455]

My #5 shattered at 202,000! Only warning was something that sounded like an exhaust leak

[@genobrn8743]

Great video- my #1 piston shirts also shattered on my 01 GC at 158k- meticulously maintained from day 1 out of the dealership.

[@freehigh3292]

You did an amazing job. I would love to learn more about Jeeps.

[@t-.mm-.]

I’d watch a video series of you and your brother “blueprinting” a 4.0. Disassemble, clean, machine, assemble and run. Full of tips and 4.0 specifics. Thanks!

[@projectbumblejeep4190]

For me, just keep doing what you do. It's all good. God bless, stay well.

[@dexjs]

Thank you for your support..!

[@admorris11]

Really appreciate all you do and how you explain what you do. Not everyone is a master jeep mechanic, so it really helps a lot of us newer guys out. I’ve got a knock on my 2001 XJ that I’m having a hell of a time trying to figure out. Doing some binge watching on your channel trying to figure out how to tackle it haha. Thanks again brother.

[@toilet4x4]

Love all the videos so far. Would love to see a full build series on something similar to your green cherokee.

[@dexjs]

I 💯 promise they’re on the list. I’m struggling with free time at the moment but I have many great content ideas. Just getting ducks in a row for now.

[@scaletrailers80]

I like how you are slowing down to explain stuff. Really helps the how too guys I feel. Keep up the good work bud

[@dexjs]

Lol thanks! It’s prolly my southern accent that your calling slowing down but we will go with that😅..!

[@wadet73]

Just hearing that engine fire up makes me want that 5th Grand Cherokee even more! Ive had 3 go past 350k miles! Keep it up Dex!

[@frankallia4495]

You gave me about 10 shortcuts. Also changed my mind about replacing the engine. I have a machine shop across the street. He’s actually my neighbor. I have all the tools you have, except for the lift can’t wait to get started PS. YOUR EXPERIENCE IS ON POINT!!

[@DavidArenivas-cx3sx]

Thanks to you I didn’t sell my jeep xj and it’s been running better than ever.

[@dexjs]

That’s awesome to hear. Thanks for watching.

[@russellsalvador1620]

I have a 96 Cherokee, so watching your channel is quite helpful, you do excellent work.

[@tidestacker4674]

Love your shop and set up, and your videos,good job!

[@bottemdwellar666]

brother you are doing a fantastic job ...knowledge is always helpful ....and everyone's tricks are different and like you said some people do it differently but for a person that is watching that has never done this stuff like we have your videos may be the one thing they needed help with so my hats off to you sir ...keep up the great work

[@dexjs]

Yes I’m starting to realize how much people love simple informative videos, and as long as they do, we will put more out there, thank you for the support..!

[@tracywisniewski1416]

Where are you located

[@rustygehl]

Late to the game, but I love this kinda content. Always learn new tricks, etc

[@joshuazientara4452]

I love every bit of knowledge you have to give. Basic stuff, super secret tricks, all of it. Thanks for sharing.

[@dexjs]

Thank you for the support, more to come..!

[@xSKOOBSx]

Watching him almost grab the hot piston rod with his one bare hand made me clench. haha

[@FrankCastle694]

That light bulb at 4:19 is the thing that has the inconsistent pitter patter😂

[@jackrussellville]

I have rebuilt a lot of engines but never a jeep 4.0, I appreciate this tutorial

[@LostmindsofBrandon]

I like that you explain everything. This is my new favorite channel.

[@jimmyjckjones]

Great content. Learning stuff is where it's at. Thanks for the lesson.

[@dexjs]

I’m definitely starting to learn that, we are obviously still gonna put out action/trail ride type stuff, but everyone loves learning for sure..!

[@gregheuer5871]

Great video -I self taught on sbc's; this is good for entry level mechanics and anyone learning faults of a 4.0 Now I know why many of mine failed

[@GaryBailey-et2ts]

I’ve got a 1999XJ limited that I’ve been trying to restore slowly, but surely she’s coming together thank you for your help

[@CrawlingArizona]

Odd knock Advice? Intermittent knocking on very low mi. early 97 TJ 4.0 - Loudest underneath rear pan area, at running temp random, off idle, mid-range, varies or disappears depending on load. knocks at idle but give slight throttle and quiet. Pulled pan, looked up at skirts all in place, nothing in pan. pulled every rod cap all good & tight bearings. Pulled some main caps, all like new. Way before, on almost vertical climbs starved oil, lost pressure and knocked at least two times. Do early TJ 4.0l like late 96 build get cracked skirts? Thanks for the vids Dex!

[@prb35976]

Good content! Much better than most. I watch 4.0 stuff mostly but it's hard to find creators teaching correct engine how to videos so I appreciate you not keeping stuff secret👍

[@dexjs]

I appreciate that! I definitely feel I’m in a different category than most people.

[@autotek7930]

That's exactly what killed mine lol. I could not find a used engine that wasn't 2k and 200k miles anywhere. I ended up buying an s&j stroker. This one comes with forged pistons...... yay. When you went to blow out the front head bolt hole I was like noooooooo

[@dexjs]

😅😅the camera makes you do stupid things that know are wrong but you aren’t paying attention lol..!

[@leopom78]

Just keep the tips, tricks, and how to’s coming. I’m learning a lot. Thank you.

[@dexjs]

More to come!!

[@jessejames9420]

Hey Dex, first-time commenter, been watching for a few months now, and I gotta say. I love your videos, thry way they are put together with the knowledge you share. Really made me enjoy these vehicles. Bought my first jeep 6 months ago and three days just bought my second (both xj). I'd really enjoy seeing what you did about the fuse box leak and how you went about the electrical bugs that come with it, ive tried a few things and just lost motivation.. Thank you for all the time you invest on this platform for us!

[@MyBbgun123]

I like learning everything I can about these motors

[@christianmarchan6577]

Awesome men you have a lot of knowledge I’d like to see more details about engine rebuild and transmissions on these 4.0 I have an 98 xj that I’ve been working on for a while now, I really appreciate these kind of videos

[@suhjested5955]

Dex I ain’t got common sense and I’m hardly mechanically inclined so I like these videos. If you could do more informational things like this I’d love it.

[@dexjs]

Honestly these are the easiest videos for me to make “editing” wise, so if there is something you want to see/know just let me know and I’ll make a video about it, thank you for the support..!

[@speedharrop5449]

My ZJ had knock I thought might be bearings. I replaced the bearings (in my driveway). I was delighted that the knock went away for half a day, and it was back. Turned out to be the harmonic balancer. When I started your video I was sure that was going to be the cause. Knock on wood my 04 WJ's pistons don't fail. Totally liked the video, especially your parts retrieval vehicle. I'd be comfortable with one like it but I don't think my wife or neighbors would approve.

[@randyderksen4358]

Your content is great - appreciate all the good tips. Piston slap and collapsed lifters are pretty common on these. Keep up the good work.

[@XiiPuNiSh3RiiX]

Love seeing this stuff especially from you, the way you describe things and dont try to act like you know everything when you explain. Just the basic what, why and how you do it.

[@themikekellett7012]

Just keep on keepin on Bud. I been wrenching on these turds for close to 50 years now and I still learn something new every day. You got the knack so show off a little, I ain't skeert a learnin.

[@moisesoroz7351]

BRO! You did an amazing job! Heads up from the beatiful state of Sinaloa, Mexico!

[@coreymaynard2747]

You are the man! For guys like me just enjoying to learn how to do multiple things for myself because I’ve never been shown much, men like you are priceless! Keep on keeping on my man!! And because of you anytime I see a Cherokee i try to buy them all lol! This ole Kentucky boy sure enjoys all your content buddy! Take care you and your brother keep fighting the good fight!!

[@kristopherkopp4568]

I just found your channel, i have a 89 jeep comanche wheeler, love seeing your tips an tricks an videos like this one just incase I'm doing it in the near future! 🤞

[@user-yj7qj1qg9j]

I did the same thing to my sons Jeep las April. It’s definitely a common problem. A friend of mine called because his is making a similar noise. I sent him this video as it’s better than I can explain it to him. Good vid👍🏼

[@johnebert2036]

Awesome job thank you. I own a 93 XJ 4.0 251.000 plus on it hit a flood yesterday water went over my roof at about 35 40 mph and kept on going love my jeep xj country

[@drew7767]

i enjoyed it, struggling with a 98’ xj 4.0 currently. #2 cylinder low on compression but doesn’t seem low enough to cause dead miss at idle at about 106lbs vs all the rest at 120’s. miss goes away above 1100 rpm or so, even confirmed with scanner no miss detected at higher rpm. probably going to pull head unless someone has any other ideas. so yeah I like seeing someone that is an expert and learning! thanks for sharing

[@wowchad]

Dex I loved it, great job! Especially enjoy the raw human stuff you leave in. Those opps moments we all do, even the best of us and most YTubers edit it all out. Extra cool w/ brother next door & seeing him doing his thing! Hopefully you never make so much $$ on the channel that it changes 😄Keep being genuine, that’s appealing & what’s missing these days with voice-over crap on TV, over edited crap here on YT…. ANYWAY I just stumbled across your video while searching for stroker info, (which I’ve been watching YT vids on for about a week, so I’ve seen plenty) za maybe you’ve already done a 4.2 crank in a 4.0 making 4.6 stroker, if not - that’s my vote - There’s some really good info out there, be interesting to see your take on doing one Duces ✌🏼

[@wordlabz]

Saving my life, one video at a time.

[@AnsleyBuilt]

Great video, always been a jeep 4.0 guy so glad I found your channel

[@joshcmichaud]

I have a 2004 WJ Laredo 4.0 with 203,000 miles. It started chattering a while back. It got better at 3,000 mile oil changes, but now it doesn't go away. I switched to T5 Rotella and a quart of Lucas High Mileage. I don't know a lot about engine internals, but I think what's going on with mine is the same as the one in the video. I'd love to learn how to rebuild it myself. This video is great. I'll be looking for more

[@Rev1Kev]

Informative video, I have a 2004 grand Cherokee with the 4.0, has 468,000miles, runs great and all original

[@hoppygoodness]

I appreciate you blending in the "basic" stuff.

[@chrispurzer9461]

What you and your brother KNOW and DO ....is amazing.

[@taduse]

This was great! Just watched the rebuild ZJ to XJ 4.0 engine stand vid. Now this vid. Great content. I just picked up a one owner 2000 XJ with 80kmi. Hoping to base line the maintenance stuff, oil leaks etc. Hope I don’t have major engine stuff for a long while. Not sure you have yet… can you talk about the early 2000s cylinder Head 0331 crack issues/overheat. Thanks.

[@user-mw6xw2ks1w]

Excellent. Thank you very much. Loved seeing the pit-falls from (onvious) prior experiences.

[@thelol1759]

Incredible video Dex, thanks for posting!

[@user-bh3nn2fy1w]

Thank you so much for your videos you explained it simply easily to understand for those of us who work on our own vehicles❤

[@strawzinthewind]

Great video! Been debating doing this or dropping in a new engine. I’ve replaced the head and oil pump before, but I can tell the bearings are worn along with some slap. I think buying a hoist and dropping in a new long block might be less work overall.

[@CrucesNomad1]

As Im in the middle of a repair, your tips are appreciated.

[@dexjs]

Glad to help😁😁

[@dansharp8042]

You sir are doing the jeep folks a great service.

[@jamesvice8705]

Love the in depth videos! Like you said the common noledge isnt that common anymore!!

[@SkeleMusic]

A master mechanic at work. Amazing content and skill here!

[@LonersGuide]

Enjoyable video, and I definitely learned a few things. You definitely pace the video very well.

[@thelol1759]

Also, I love this type of daily mechanic stuff, definitely keep it coming!

[@dexjs]

See I been holding back on the mechanic stuff. Didn’t know if it would be boring content.

[@thelol1759]

@@dexjs Nah man, I cant speak for other people, but I live for this stuff! Thanks again for posting!

[@robertpraegitzer4362]

Wish you were in my home town! Good mechanics are scarce. The few good ones are always busy and behind schedule.

[@user-kp6ig5rq5i]

I regret selling my 2001 jeep I could have made a rebuild motor if I had just seen your video like 6 months ago but I'm thinking about buying another one cause u just gave me the game on how to rebuild a motor thanks

[@edvillela5197]

Great video. I appreciate you sharing your time and knowledge. Thank you.

[@williamdavidson1456]

quality video my friend you make it look easy, its great videos like that that will help people learn and have an idea how to do jobs like that to be a mechanic. its a bit out of my league to do but great to watch thanks for that.

[@koreywilliamson3737]

Love the tips and tricks videos I've always had a 4.0 in all my rigs can't beat them

[@dexjs]

I really appreciate it. I’m not gonna stop them. I love helping people out.

[@Dragnssmoke]

yes love these videos i have a 93 jgc and i want to do the same thing to mine just to freshen it up but this is the only thing i have never done on my own before so after 35 years of wrenching i think its time i try rebuilds and head work was just something i would never do

[@user-io5kz6ep7y]

Just found your channel and great content. I have 02 Wrangler Sahara 4.0 and working on issues. I am positive I will see issues I come across on your channel. Thanks and keep on truckin great channel.

[@dexjs]

Thanks for the sub! Definitely got good info to give out.

[@user-io5kz6ep7y]

@@dexjs looking out brother thanks

[@robberry4670]

Grate to watch your independence with the 4.0 And it really helps As we say in Australia Thanks mate !! 🙃

[@u4ea1982]

Awesome video - very informative and entertaining. Keep it up!

[@MikeHensley-sc3ns]

Damn… you make it look easy and not time consuming. I guess the lift really speeds things up. Nice job!!👍🏼👍🏼 Earned a sub fo sho😜

[@cookerbullock]

Man.. it was great, I washed dishes and cleaned the kitchen listening to ya….. I think I subscribe.🎉

[@dexjs]

Learning and cleaning, that’s awesome!! Hope to keep the videos entertaining enough to learn something.

[@classicklyjus1025]

I love your content. Thank you. Very insightful

[@tidestacker4674]

I have owned 2 jeeps, 2017 4door wrangler rag top new, sold it and got a truck, brought one new in 2022 another wrangler hard top was a 4 cly didn’t like the start stop and sold it as well, just bought a 2024 Ridgeline sport trail, like it, has the v6 280 hp not a turbo,probably sale after a year, don’t like what they did to the Jeeps , over priced, but like what you are doing with the older ones! Better than the newer ones in my opinion!

[@Skipper51]

I just replaced my head on my 2000 Cherokee, and I was wondering if the Pistons were bad. What would they sound like? This answers those questions; they don't. I loved the basic talk to me like I'm a beginner because I am.

[@TheMainLead]

I love watching this stuff. I’m excited for the heads video I have a 99

[@lafonax3813]

damn you got a badass setup with your brother being right down the road

[@danielmcclain1573]

Keep the video's coming !! Great content !!

[@dexjs]

Thank you! Will do..!

[@americawehaverights3926]

IT WOULD BE SO DAMN NICE IF YOU LIVED IN OREGON. I appreciate you brother.🇺🇸

[@OldSchoolJoe26]

Loved it ! Was very informative. Keep up the good content !

[@dexjs]

Thanks so much. I’ll get better. I love spreading what I’ve learned over the years.

[@chuckguerrero6338]

i have a 94 jeep cherokee 4.0 and im learning from you , please keep it up.....

[@anewhall100]

I’m driving a 99 Jeep Cherokee with the 4.0 I it with 232K on it. I’m thinking of doing a very basic rebuild on it as the body is in good shape anything I can learn about it is great.

[@michaelc6522]

Good video I have rebuilt a few jeep motors 4.2s and 4.0. I think the head bolts are torque to yield and should be replaced with new ones. I found that if you take a couple of old head bolts and cut the head off and put a slot for a screwdriver in them and screw them into the block it holds the gasket in place and guides the head on.

[@ForceBuilt]

Just found your channel and Subbed. I actually worked with Justin at Cat(well in the same building). I Had a broken piston skirt on my Jeep Tj. I did the rebuild on my channel. I have been interested in an XJ for a while. I need to come up sometime(from Corinth). Keep up the great work!

[@Kdjeepzj]

Enjoying the videos, I’ve been learning a lot from u, thanks man

[@dexjs]

Glad to help

[@796andy2]

great stuff , been binging your vids

[@ravenbarsrepairs5594]

It's piston slap. Pulled mu oil pan on my 268k daily driver, and found the skirt from Piston #4 in the pan. I've got a 97k spare engine in the garage that will be going in. It took me a good 11hrs today for me to get the old engine pulled. Now I start waiting for the gaskets and other parts I need to put if back together. I've got plenty of other work to do inside the engine bay while the engines out, and also some auxiliary electric upgrades to finish, as with the engine out of the way, I'm hoping to find a place on the passengers side firewall to run an 8g cable into the cab to replace the 12g wire that feeds my aux power panel, and moving/replacing lights around, so the Nilights that have been on the roof(with failed finish) move down to the foglight position, and 4. new Nilights go up on the roof, 2 replacing the moved ones, and 2 replacing the DIY 18" bar I made out of a mangled 4' bar that has no voltage regulation and several LED's have burnt out since.) Unfortunately the parts I have on order won't be in for over a week, so I expect I'll be tearing the old engine down while I'm waiting for them to arrive. I know that Thumper had (as a coworker called it) a "Death rattle" for the last 50k, so I expect to see some carnage. I always thought it was just badly worn lifters, to the point that if the transmission didn't die last summer, one of my plans was to pull the head and replace the lifters.As I ran the Jeep ~45 miles after the sound started getting really bad, I expect badly scored cylinder walls. Personally, I disagree with a shop doing this type or repair, as I'd expect cylinder damage; likely major scoring, but even an oval'd bore which is an earlier sign that the piston has been rubbing the cylinder walls for a while. When I pull the old engine apart, I fully expect cylinder 4 to have major scoring from the broken up piston, and prehaps other cylinders have ovaling from piston slap as well.

[@edkenny3154]

Thank you for the video. Right to the point and informative. I am going to replace the pistons in my 99 Cherokee as soon as the weather breaks. Is there a specific part number that you would recommend? I see that Sealed Power has a few options.

[@dawoodk103]

Boy, u c that bulb flickering behind u ??? Any way u boys r a winner, hope u 2 brothers go a long way together in life. Where is your good old shop in America ???

[@Deezy29]

Hey dex, love the channel man keep it up. I have a wj and an xj, my wj tapps pretty loud but as soon as it warms up to temp it goes away. Would piston slap go away like that? I always assumed it was valve related.

[@KyleSVT]

Great video man Really enjoyed it! Subbed

[@robertfitzkee3862]

My 91 jeep xj 4.0 6l driving if I mash the throttle it makes a rattle or tapping sound only high rpm to take off fast it just started it about a week ago. Plus now it's starting to buck and spit. I changed the sensor on throttle body it didn't work but check engine light went off and it started again new fuel pump in still doing it. Every one is saying heat soak. I had this jeep 3 years why is it doing heat soak now and didn't then. Thank you. Love your videos

[@jeepdoctv]

Awesome video dex!!

[@Motorcycle_Man]

That was awesome, u and your brother are so clean also. I like that

[@nickaxe771]

I like your style buddie...real cool. Nick in the UK.

[@MechanicalDifficulty]

Big thanks! My 2.5L mystery knock is no longer a mystery.

[@iloveinheretence]

I care about the explanations, you've helped a ton friend.

[@dexjs]

All new to me. Learning!!

[@eddytoy9496]

Best Jeep channel on the tube.

[@dexjs]

Appreciate that

[@earlbucklin8323]

you all really got it together.......... thanks

[@thehogpin4044]

ALways enjoy your videos