Re: Jeep Engine Noise - EricTheCarGuy 

Hi Eric the car guy I just wanted to let you know you that you helped me a lot while I was in jail , I had access to a learning tablet that had a whole bunch of educational videos of different types of jobs one them was yours , had all kinds of videos of how to fix different things

I'm a old-school mechanic it's a very simple fix for that noise before disassembled the cylinder head you must #1 drained 2 quarts of oil then add 1 gallon of diesel let it run for an half hour then drain all the oil with the diesel #2 remove the cylinder head replace all lifters and lifter rods #3 install everything back put Ina cheap oil 🛢 filter put 5w30 oil 1 can of mineral oil Let it run for 1 hour drain the oil get a good oil filter good oil and the ending will be very satisfying I personally have rebuild plenty of these 4.0 they are one of must strongest engines out there 😀 mark my words

Had the same exact noise this past weekend after, and only after, changing out a cracked cylinder head and 2000 Cherokee. I was helping friends do the work to save them some money. They elected to use the old spark plugs which were well used & AMA (against my advice). The noise was a "knock" like a rod rather than a "click"like sticking lifters I'd heard Before. Using a stethoscope I mostly convinced myself the noise was high and near cyl #1 or #2 but the tone of the noise, the location and the absence of the noise before pulling the old head didn't add up. I was stymied. I suggested some Marvel Mystery Oil and a trip to a professional mechanic. My friend, a novice mechanic, decided to go ahead and change the spark plugs when he got home. The noise stopped! Don't know if it was a bad plug or a bad connection to the coil bar which caused a firing problem which caused the noise. Can't explain it because I am not experienced/smart enough; but, the noise went away.

I've got a 96 2 door with a 5 speed and 2 wheel drive. It may not be able to crawl over rocks but it's driven over something hardly any other vehicles have... over half a million miles of highway. It gets around 20 MPG and after all those miles and over 16 years I STILL love driving the thing!

honestly , as an apprentice, I find myself often referring to your videos for a second opinion on fixes, and things that go wrong with my own vehicles, often you've been more informative and accessible than even the journeymen i work under. Being a young tech is a rough start .. not an easy world to work in. having someone who knows what they are talking about to reference makes a huge difference. so thanks for that man.

You're still great at what you do, regardless of what everyone says. Every video I've watched has helped me extremely with my issues. Thanks for taking the time to do what you do!

Man. I bought a 2002 jeep grand cherokee with the 4.0 in it and it was making that same noise. Girl I bought it from said 3 mechanics looked at it and all said it was Ricker arms went on rockauto and ordered new rocker arms, lifters, pushrods, valves, valve springs, head gaskets and bolts, intake and exhaust manifold gasket, valve cover gasket, new plugs and the coil pack and a new goose neck with thermostat. Did it all, didn't change a damn thing. Dropped the oil pan, had 1 spun bearing. Cha he'd all of those and it runs like a dream now. Just irritates me when others know everything a d they weren't even close. Nothing against you, the 3 mechanics who were calling it a top end problem and it was on the bottom. And I'm convinced someone was stoned when they designed the intake/ exhaust setup.

I studied auto mechanics while into prison on Sweden for 6 years. Your videos were and are inspiring. Thank you. This why my English may be terrible, I’m sorry! Been work hard and studying for license and shop! With that said to you, thanks you!

please i hope no one cancels injectors individually by simply unplugging them!! Chrysler uses positive side switching. for those who do not know what that means; if you simply unplug and injector while the jeep is on there will be what is called a power surge in that electrical system which has a very HIGH potential to burn out your computer. the only safe way to unplug these injectors is to turn off the vehicle and wait a few minuets. then unplug one injector, and start the vehicle again to proceed with the test. you must turn off the car completely each time you want to unplug, or plug in an injector.

So what was it? Valve? Lifter? Bearing?

Two Pistons Skirts is the Answer from my personal experience. When the 4.0 over heats its common for the two front pistons to warp as their skirts break apart. My WJ when it first over heated i pulled over waited my WJ said it was normal temperature again. couple miles later as i was driving it started to over heat again then i started to hear a knock noise appear as i pulled over i lost power waited an hour turned it back on it starts and runs but knocks so i towed it home. Took my Valve cover off nothing, my Engine's Head nothing so, i checked my pistons and only the first two were damaged. Replace the two and there is no longer a knocking.

thanks dude, all your time and effort showing good info for amatuer (shadetree) mechanics like myself is appreciated, ignore the idiots that spend more time being critical than posting anything useful.

What the hell is up with some of you guys?? Give the man a break. Thumbs up Eric.

My 2011 jeep compass 2.2crd sounds exactly like the one in this video and it happened after it overheated due to heater core failure and I broke down on the motorway. This 4x4 has caused more problems than I’ve ever experienced before and I am sick of it and I am ready to sell it for a huge loss and I think I am going to go back to the old Suzuki which are a lot more reliable. I have had a no heat issue for 3 years now where it started intermittently then for the past 2 years I’ve spent a ridiculous amount of money on trying to it sorted and now I have no more money to pour in to it. I have spent thousands on it with everything I’ve been told is the problem, then after it costing it turns out to be something else and so on. I have been to a few so-called reputable places and I have had all the tests done and even had it doubled checked at Jeep, and it were showing up as heater core problem so I purchased a new heater core whilst at Jeep but couldn’t afford the £1800 for them to replace it and they told me it will be a lot cheaper to have it done elsewhere. Unfortunately it is a big job with no easy way around it and I simply cannot afford the quotes I have had so I may try another flush then get shut if it doesn’t work out. The bodywork of my Jeep is immaculate and also the interior with full leather seats etc is beyond beaut in my eyes so it would be nice to keep but I just can’t afford to spend anymore money I haven’t got on it anymore,. To replace this heater core all the dash has to come out and it will take at least a full day for any mechanic replace it so no wonder everyone wanted to avoid fixing this issue for me.

There's not enough zinc and phosphorous additives in modern engine oils to properly lubricate flat tappet engines (of which the 4.0L inline 6 Jeep engine is). The engine ticking noise is a worn out cam lobe hitting the bottom of the lifter because of excessive clearance. If the proper additives were in the oil since the engine was new ( and at every oil change, of course), there would be less likelihood of worn out cam lobes, thus ticking. I figured that as soon as the customer received his Jeep back from Eric, and a short time later the engine seized, the lifter jammed the cam and stopped the cam shaft from spinning.

It's a shame u have to explain yourself. I get this sometimes. A bit like "since you serviced my car my air freshener doesn't smell nice anymore"

low end knocks like that are usually a main or rod bearing, I had a similar problem with the neighbors 99' Ford F150, ended up pulling the engine and replacing the main and rod bearings.....its just as you pointed out Eric, you can only do as much as your friend or as in my case your neighbor will let you and how much they want to spend......

would have been a great candidate for scannerdanner. He would have set some piezos on the engine, captured data and graphed it to find out not only the noise location via a series of captured db levels but also tell you what other events were occuring at the exact timeline. ie .. the piston travel positions and engine timing events. damn

Eric, one thing I found out about Chrysler products is something I have never seen with any other make. If you re-use the torque converter bolts you are supposed to grind a thread out of each bolt. They don't give enough depth of thread in the holes and a used bolt will bottom out. They aren't TTY bolts and can be reused but must be ground. I also have in my shop right now a 4.0 that has a shot to hell timing chain with tons of play but no driveability issues, another thing I have never seen in anything but this particular engine. The timing chain failed due to heavy sludge, which was loads of fun to remove. Love your vids and what you do, but I do realize that maybe you aren't as deep into the 4.0 just like I am not in deep with knowledge on import cars. Thought I would throw some info your way. Obviously without the engine available for an autopsy we will never have conclusive proof what did fail.

Wow Eric. You hit all parameters answering the comments on this one. Good job.

I have come across a few of the later Jeep 4.0's that had the same noise. In all of these cases, I found that the cylinder head cracked, which caused coolant to flow into the oil. And as you know, it doesn't take long before bearings and anything else lubricated by oil to get destroyed or wiped by coolant contamination.

Hello from a mechanic in Denmark... I think it sounds like the connetion rod bearings at the crankshaft... Great videos.. Keep up the good work... :D

in my experience , most chrysler products aren't very good at detecting mechanical issues through sensors due to wear. In essence they are however excellent at compensating for this wear. They will show performance loss , yet not with accompanying sluggishness. However , timing chain noise would never be this loud , and if the engine was out on mechanical timing , you would be able to detect this via the catalytic converter. When Chrysler timing chains wear , the computer compensates , this causes the engine to run rich , thus the catalytic converter will cause the sulfur smell , and overheat. That being said , all newer Chrysler products after 1989 usually were equipped with a timing chain tensioner which could have caused this noise. Without tearing it down , it is impossible to note that this could have been the problem. Although I would have liked to have seen this being torn down before heading to the scrap yard , but i do appriciate the video , i enjoy doing refresher vids before delving into a project , it helps remind me of any short cuts that i may have forgotten. Great video , thanks.

Eric there is one more thing about ticking noise if it sounds like it is the lifters but to soft you should do a drop off the oil pan and hand crank the engine so you can see with a flash light up to the piston if the piston is worn on it's side which is a common issue when you run this jeep thru the mud and get dirt into the engine block. It works like sand paper and so the ticking comes from the piston been worn and each top dead center when you go from push to pull it tick's the cylinder from one side to the other side. Just as a FYI for the future for you and others to know. Over time it creates a blow by to the point of engine blow up or total power loss. If in the early early stage you find out it's only the cylinder which need's to be replaced. Later you need to machine the block for bigger pistons with a machine shop.

My AMC Comanche made that exact noise at 260,000 miles. It also was running fine one day and then sounded like that the next. The engine threw a rod less than 50 miles later before I could have it looked at.

People gave you crap for only doing the minimum and saving the owner possibly a lot of money? Seriously? Those people are clueless, man. You did exactly the right thing. I am saddened that you felt you had to justify a solid business and mechanical decision. Despite ill-considered RU-vidr comments, this friend/customer will *trust* you precisely because you did not take lots of his money so he could have you essentially polish a turd. Again, solid call. Good job, sir!

Why are people so mad? Enjoy your great free videos for fucks sake!

Great summation and as a retired Tech I agree , you cannot just go ahead and repair as the cost issue can be the key, and viability of repair, your call proved correct. It would be real nice to find out what did happen internally !

@EricTheCarGuy You know what man.. there will always be haters so just push them a side. Really your the one that is working on the Jeep and you know the owner real well and you said that you have done several things to the jeep and you know the car better then we do. So anyway keep doing what you do. Thank you for all the free videos they have helped me and several other people so me and other people thank you! :)

It definitely was a bad flux capacitor!!

Jeez, Eric... Just read through the comments... Didn't realize there were so many experts out there, I feel for you. Keep up the good work and don't forget to clean out your B.S. filter =D

Hey Eric, let me tell you something that happened to me. So I was watching your videos and my grandfather walked in and asked "Are you learning about cars?" Me: "yea I'm on RU-vid" Grandfather: "oh, and how much you pay to watch this?" Yep, Thanks so much Eric to make me and so many more people repair their cars without paying anyone and having the joy of it too.

for me it was Driving on the freeway, Engine just totally died out turns out was running with no oil in it. THAT noise started.

owning a jeep with a 4.0 myself, i have done some research. those 4.0's generally wear out right around 200000 miles. mainly its lifter problems, but it is usually followed by a lower engine knock pretty quickly.

Keep up the good work eric, I'm a 20 year old DIY mechanic who just loves to learn, and you are by far my #1 source for info. great job as always!

2 of 2 From what I'm told, the head cracks and warps ever so slightly , and it puts stress on the lifters. We since then replaced our engine, $2500 later, and our jeep is back on the road. The engine had 86,000 miles on it, and the jeep has 192,000 on it. The reason why I'm saying a stuck lifter is because they wouldn't move at all afterwards. But after it cooled down, and was towed to the shop it sorta ran again.

If the hydraulic lifter was bad it could cause a loss of power by not alowing the valve to fully open, and will cause top end noise. Bottom end damage usually makes a knocking, or thumping noise instead of a ticking noise in the top end, in my experience as a diesel engine tech. You have to take it apart,clean and inspect to know for sure, and thats all up to the customer, and how much money they want to spend .

My 4 L has a broken piston skirt and It got worse over 3 years and now I have to fix it , however I only want to fix the one as the rest are still Ok, The Jeep is almost done so what say all you Jeep owners? Should I just change the one?

my hats off to ya eric. you have to be a smart dude to do what you do. after reading through my quest's service manual and dealing with the O2 sensor problems and such, it's VERY complicated. There is a lot going on inside a car, and they are very impressive in design and function. you're very good at what you do

ERIC I have this same type of vehicle. I drive city type driving all the time. I change engine oil little more often then it recommends and now have 137589 miles on it and it runs great. You being a pro can and should tell is a vehicle is proper maintained. Oil to me is cheap insurance for engine life. If there is a problem get it fixed right away or it could lead to serious damage.

1998 XJ 251000 miles, running strong (knock on wood). Had a car make this noise, drove fine before the noise, parked at home, hour or so later went to leave and that noise happened, then engine blows... piston skirt pieces in the oil pan, top of piston and the header made contact and shredded to s@#t. happened in two of the four pistons. kept the "best" piston too. put used engine in, runs great! sold it to my sisters family makes long trips to this day!

Eric, lo que aprendo con tus vídeos es enorme y nunca dudaría de tus diagnósticos así que no le des importancia a los sabios que comentan sin saber la historia de ese auto. Greetings from Argentina, you're the best by far. I'll dare you to use the google translator! solo quería que sepas que veo todos tus vídeos a 10000km de distancia!

Oh, and when I replaced the engine in my 1980 Pinto, I did pull the oil pan off the old one, and sure enough, there was 3 pieces of the #2 piston in the pan, broke off at the oil ring. Strange thing was one of the cracks was very shiny, indicating that it had been cracked for a very long time. The rest of the pieces had very sharp crystallized edges showing a rapid progression once it decided it's time was up. The block was too deeply scored, so got a used engine from a mustang.

Balancer hitting the timing cover? sounds like the jeep i just changed a balancer on

Wrist pin or broken piston skirt are VERY common and sound like that.

Yes you can hear the rod knock clearly on the video. And it engine later seized up confirmed the case. I just hope the Eric can get the Jeep pulled back in again so the can show the views how a sprung bearings in a 4 litre looks like.

Hey Eric it's William from MustangMedic, thanks for the AC video we are deep into it on a 69 Mustang.

If the noise was coming from cracked or loose flex plate the noise would change ALOT by putting the trans in drive or reverse while the engine was at idle speed.

It now has 302000 miles, and running strong. Just did the lifters, rings, and lower bearings. Suspension was all done a while ago. ready for another 100,000

Had this very same thing happen a few months ago. Jeep engine quiet and running good to Jeep engine knocking and clattering. A BIG mystery for quite some time. THEN over breakfast one morning the owners son mentioned that he knew the Jeep was Toast! and long before it started making noise. Said even he had tried to save it. Said he noticed a DROP of oil in the school parking lot. Proudly stated he had picked up a can of stop leak and poured it into the engine. What kind of stop leak? Slime

Well it did, but a SPOA lift with wheel spacers and 33s fixed that quite easily, and the sidekicks (my toy of choice) fixed it because the top was narrower than the bottom unlike the Sammy. I live in the south and I see rust-free ones on Craigslist all the time. But they are pretty expensive. But think of what it's used for. It's a miracle they lasted this long when they're mudbogging and plowing snow and fording rivers all the time. My 89 Sidekicks got 34,400 original miles.

All Jeep 6 in Line 4.0 L Engine Noise is coming from the Pistons Zuiger when the zuiger is moving form left to right . I Recommend to Replace all Piston and Zuiger kit in all Cylinder. The Noise starts in the Cyl 5 and 6. The noise is coming from the bottom of the part in the back. I hope this will resolve your problem.

your totaly right about it not being a timing chain every loose or slipped timing chain I have seen has had a cam code in the pcm. I work at a chevy dealer and the timing chains on the 3.6 engines like in the camaro and traverse and acadia are known for stretching and what tells me they are bad is a cam sensor code .

Cars break it happens. Your a good guy Eric keep up the great work.

1 of 2 One thing I have found out is that these jeeps have chronic intermittent overheating issues due to the electric radiator fan connectors. I fixed that in ours, and it hasn't Overheated again. But about 4 weeks later, the engine let go. The rapping got louder, and changed noises, then died completely. The damage was already done. The cause after taking apart the top end was the head cracked between cylinders 2 and 3.

I have cracked and broke flex plates and though it was rod. Currently gotta change flywheel because starter not catching. Those value covers always loosen up on jeeps. Of course I got 700$ jeep 3 years ago. I always like your videos. Thanks.

Thank you also for following this up as far as you can. It would be a real education to have you take this apart and see what's there. Maybe you can buy it from the junkyard and have a look, then sell it back to them after you are done, ha ha.

Regardless, that thing was shot. The two options were junking it or replacing the motor with one from a salvage yard.

Timing chain has a rubber piece mounted in cover that breaks apart allowing chain to tap cover, would not, I repeat, would not effect performance. I know he said he would not respond to this, thats fine his loss. Being a experienced mechanic myself, I tend to investigate reasonable comments, instead of arrogant dismissal.

My car sounded like that once. It was low on oil, and after filling it back up, it's been perfect and noise free for about 30,000 miles.

Is there a betting pool for this, yet? :-D I'm willing to bet that the initial problem was selective oil starvation. It doesn't happen often, but I've seen engines in which one specific rod bearing doesn't get oil, causing the bearing to fail. Further, that rod now isn't squirting oil on the cylinder wall, which kills the piston/rings, and causes a cascade failure putting more tension on the rod. The sound in the vid seemed like a single, large item; not a valvetrain sort of noise. :-]

awwww I was hoping for a tear-down.

Ever ask him what he did to it, or rather didn't? My guess is the engine had been overheating for a very long time. I takes work to kill a 4.0.

Definitely piston skirt slapping problem then it broke with catastrophic results. Very common noise in those years with some folks having the noise for years without breaking. Its been a few years but I think it was piston 5 in mine that broke and scored the cylinder walls so deep that I couldn't do a rebuild on the engine unless I wanted expensive cylinder sleeves . Engine was at 125K miles.

you the man eric! it's great you do these kinds of videos for your fans.

The GM HFV6 engines also throw a code if the timing chain stretches , there is a software update which can be a temporary fix for them , but i think it's better to replace them , and there's more than one as they are a multi cam V6 , so it is not cheap , but some dealers will meet part of the cost , m y own dealer does them for $1500 NZ Ruble's

I have a similar noise but more from the oil pan area? Any thoughts?

Those 4.0 Jeep engine are junk look what happen to this Jeep knocking noise for unknown reason .. The best engine bulletproof are the Ford 4.0 SOHC engine .

I have a 4.0 and its making some noise coming from the top end. (I think) but you can't hear it at idle and only when you rev it. I'm so lost.

Bloody oath it sounded like a top end noise ,well worth a look under the rocker cover . gota love backyard experts they make heaps of work for real spanner swingers!

Old video, but it had to be a cracked piston. Those things appear over night, and can grenade an engine.

I thought it was the carburetor belt...

Broken piston skirt/piston slap. Even common with the 4.0L

Probably piston skirt.. the 4.0 was redesigned in 99.. they changed the piston castings, and they were bad. also changed the head casting at some point they tend to develop a small crack in the coolant space, and bleed coolant into the oil under the valve cover between cly 5-6. The 4.0 was a bullet proof engine, but 99-04 has the potential for serious issues

It was either bad lifters or connecting rod bearings.

I agree with your train of thought. With that many miles if it's not the top end = rebuild the motor, replace with salvaged engine, or junk the vehicle. I'm thinking it's a spun a rod bearing. My GM 4.3 Vortec spun a rod bearing and sounded similar. I could have sworn it was pushrod noise at first. At TDC the excess play makes the slapping noise. The connecting rod acts like rudimentary tuning fork which makes it sound like top section of the engine. It louder below but that's not where people put their heads. A stethoscope helps as you mentioned. An unsolved mystery unfortunately.

I know that the engine was toast, but it was a great how to for the valve cover removal. And the paper clip idea is a great idea, I would of never thought of that. Overall, great DIY on a bad engine!

probably put a window in the block, seen that multiple times from many 4.0's with a cracked piston skirt. usually cracks from lack of coolant and oil changes. wear on cylinder walls and excessive heat weakens the skirt. the piston bounces around making noise, rod cracks... piston puts window in block. their tough motors when taken care of. modern oils don't protect the flat tappet cams in these motors.but a worn cam lobe or dead lifter wont cause a dead engine, just a dead cylinder. a loose timing chain will cause an erratic idle, misfires, but once again, unless it splits, will not cause a dead engine. also these things suck at picking up variations in cam timing so no code for the cam sensor but you will have a misfire code. just my $0.02

I had this happen to my toyota 22r truck last week. It started off as a sticky valve which explained the reason why it went away and then came back as described in this video. The sticking valve was eventually hit by a piston and kept the valve stuck open. The car wouldn't start after. No compression so it just turned and turned. The tapping could be the piston hitting the valve.

well said Eric some people don't understand that, most of time when they thing they know all about it, because they can change parts.

I had a 98 Grand Cherokee Limited 4.0l with over 300k kilometers, all 6 cylinders had compression within specs, and ran like a champ. I had to scrap it for parts because the rear diff crapped out on me. The 4 liter is an extremely reliable engine. Change the oil and don't beat the shit out of it, and any car will last a long time.

I never had seen a 4.0 with a broken flexplate yet.1999 to 2004 4.0s had bad cylinder heads,casted wrong.#6 piston is well known for breaking first in the 4.0s.The 4.7s,drop valve seats and is Chrysler's fault.The valve seats were installed loosely and Jasper fixed this problem.

99 XJ.... Best year of all of them!!!!

thx for the update Eric. rod bearing should have triggered a low oil pressure light or buzzer. probably piston.

22mpg huh? is that idling or when not running?

Every jeep 99 and newer had those crappy engines that Chrysler switched because they were "cheaper". Everyone knows older 1995-1998 Jeeps were the best years every built.

Don't sweat it Eric!! YOU give a lot of free advice that can help a lot of people!!! So as a very smart Tech says ( stay dirty ) LOL. Keep it up. Love ur channel brother!!!

I have a 2003 Jeep Cherokee that has a ticking noise on top of the motor but quiets down after I run it

I doubt it needed just a new bearing. There was probably a significant amount fo wear on the bottom end. I dont see any of your youtube videos of you repairing or diagnosing anything,

LOL people say Jeep 4.0 straight line engine is very reliable engine. Reliable on what making noise lifter going bad, crack head gasket and engine rebuilt at 100k,miles? The most reliable engine I had seen on American cars is the Ford Explorer , Ranger 4.0 SOHC this engine will go 200k miles or more with out a rebuilt or engine noise.... Ford make great engine and vehicles.

Buddys jeep wj simlar issue it was number 6 cylinder broken piston skirt if you would of used a micro camera to check out pistons u may have caught it in time

i got a ford focus lx 2005 with a engine rattle when it idles, i put my hand on the cam cover thing and it stops, how do i titan it or fix it? thanks Eric, Stay Dirty

Is that a common problem with that engine 4.0ltr? Because I just came across a Wrangler YJ with the same engine for sale and was planning to buy it.

I love these re: videos Eric keep doing them !!!

Eric I have a 2000 jeep with the exact same motor and it made the exact same noise. everyone that looked at it thought it was in the top of the motor we even used a stethoscope to try to pinpoint the problem, so I drove it home and it lost all power. turns out on mine it was a crank shaft bearing, it destroyed the piston wall so i had to replace the motor.

That was connecting rod knock. Need to use plasti-gauge to check clearances on all the caps.

Any chance of a cracked flywheel? I've heard a similar noise on a 5.3 Chevrolet that was a cracked flywheel.

Please help me with this problem electric Vibration Cherokee Patriot 2008

Most last for a while but i have seen a few that passed on, too bad with that one as the body looked clean on that GC, could have been a good candidate for a NEW motor-- i have a 96 ZJ 5.2 with 130,000, runs like new

good re eric.......thanks for posting......hope we find out what happened to the 4l....have a good day sir