That Sounds TERRIBLE! - Bad Engine Sounds. What They Mean And How To Make A Diagnosis On The Fly 

I've been able to diagnose engines, electric motors, hydraulic pumps and power units, bearings and pretty much everything that moves by nothing more than sound since I was a kid but you still managed to teach me something. Thanks Tony.

As soon as you mentioned the early Buick 3.8, I knew you were gonna say the damper was the problem. I did the exact same thing, but I didn't get as far as to completely pull the engine. I was just gonna pull the balancer to give myself more room to pull it, and noticed the broken damper. Customer was super happy that I noticed that before the engine was on a stand.

Tony the best thing I've found to listen to the sounds in an engine is a mechanics stethoscope, but you remove the metal rod it comes with, and stick a piece of 3/16 brake line in it. I could pick up everything it was amazing. Also a while back I bought a 75 coupe Deville that sat from 1979 until 2018, I started it and after a little tapping, the motor was smooth as hell and quiet, until you revved it. It sounded like a bad rod knock, I ran it down the street to get gas and it wasn't registered, some one pulled out in front of me so I punched it to avoid the accident. I thought I was going to send a rod out the side of the block. All the sudden the noise went away, it was a stuck lifter.

Many of the old Pontiac Iron Duke 151 C.I.D. (2.5L) 4 cylinder engines used from the 60s through at least the late 80s in various forms were notoriously noisy due to having a gear drive instead of a timing chain or belt. They actually do make a rhythmic sound that mimics a spun rod bearing. However, while it does indeed change with engine speed, it doesn't get worse over time. I also had a Ford 300 straight 6 that was so worn out that the piston slap on cold starts sounded about like 6 rocks in a coffee can! That old truck had been used and abused as a dry cleaners delivery van for at least 10 years, and God only knows how many miles before I got it (for REALLY cheap) so, I just lived with it. I ran it daily for another 5 years or so before it finally couldn't take any more...Rust In Pieces Ol Reliable!

Tony, This video was a wonderful, well oiled, version of the old videos you did .... like the porting video and the valve grinding videos. This is absolute gold! This is the knowledge you provided early on, but now in a more polished form. Outstanding! Keep these types of videos coming... and maybe throw a stunt carb now and then.

Even though I'm merely a shade tree mechanic and will never do most of the services to a vehicle that you explain. I still enjoy watching and learning.

I had a tick tick tick sound that at first I thought it might be lifter noise. Was very pleased to find a couple of loose header bolts at the number 7 cylinder. It had just started making noise so I lucked out and didn't even have to replace a burned gasket. Just snugged them back up (checked all the others) and problem solved!

Thanks Tony. As an old man, I knew a lot of those but not all. Appreciate your time invested in educating everyone.

Bingo on the flex plate. I had a Chevy 305 that made a sound like a cowbell in park but quiet in gear. I learned it well because I had to replace it every 35-40K miles. Replaced it for the last time at 120K and sold the truck.

1964 17 years old and had a 1956 chevy 265. Had a bad knock in it. Finally figured it out. The pushrod that goes between the cam and the fuel pump

I sincerely thank you for sharing all your knowledge about vehicles. With how you explained the process leading up to a spun bearing, I now understand what it would’ve taken to put my father’s 1999 Buick Park Avenue back on the road. It had about 110,xxx miles on it with a spun bearing. I always thought it would’ve just been as simple as pulling the oil pan down, replacing the bearings, and putting it all back together. Now, because of you sharing your knowledge, I know I would’ve been in over my head back then. I never realized (until now) that I would’ve had to take the crankshaft out of it too, and either have it re-machined with oversized bearings or get a new one to put back in. Without doing that, the new bearing would’ve just spun soon after installation. Again, thank you Uncle Tony.

I purchased a rust bucket '72 Dart in 2014 and it had an .040 over bore 318 that was otherwise stock and made it a father son project for my oldest son and I to work on. In approximately 2016 he bought a used (thrashed) BMW and parked the Dart. Fast forward to this summer and he has decided to get the Dart running again and start driving it as a "Rusto-Mod" with a roll cage to reinforce the body and keep it straight while we (me) remove and replace rusty body panels. Now we have a BAD noise that started after he drove it to work the first nice day we had here in the PNW. At 59 I am a little bit younger than you are and don't have as much experience with other makes and models, but I have over 45 years of experience with Mopar A, B, C, and E body cars with everything from "the leaning tower of power" to the Gen 2 Hemi. After he returned home from work the first time I heard it making a very strange sound. I don't know if you have any kids but for some reason it is my fault that I didn't hear and diagnose this problem sooner. My latest theory is that it may have spun a bearing blocking off one or more of the oil feed passages in the crank. He mentioned that when the sound really got bad for the first time the oil pressure jumped from 50-55psi up to 75psi almost instantly and I think that since the oil passage is being blocked by the bearing, the oil pressure is higher in other areas. Maybe I'm wrong with my diagnoses, but now he is all pissed off after spending over $3500 to get it running again and still has nothing drivable. Either way we are going to have to pull the K-member with engine and tranny and go through the engine. I am not sure but he just got brand new Mickey Thompson drag radials on the back that are pretty wide and sticky for this car and I wouldn't doubt it if he didn't try to do "just one burnout" and over stress worn main or rod bearings.

Uncle Tony, you need to write a book about the home engine builder series! You are a wealth on knowledge. Thank you for making these videos.

You're a freaking genius, Uncle Tony! Thank you for the education. I'll have to rewatch this one a few more times.

Tony, I've had the same kind of a knock from a fractured flexplate. Big knock knock. Thankfully we caught that before we disassembled. We did do the exhaust gaskets ( they needed that) and resealed the intake too. Saved big bucks in the end for a good customer.

tony, ive been subscribed to this channel for like 5 years now, and never commented anything, But, THANKS, for everything, your knowlegde is priceless, all the information you put out has value to it, THANKS, THANKS AGAIN, !!!!! hello from brazil !

I had just rebuilt a stock Chevy 350 and it's on the engine start up stand and when I started it up the first time I heard a clunking sound and immediately shut it down. I then took the oil pan off and checked every rod and found nothing ( no spun bearings and clearances were spot on ). So put it back together and started it up and it was there again but this time I left it running and walked around the motor and you'll never guess what it was. One of the rockers was hitting the vent box on the inside of the valve cover. took it off and bent the metal over enough to clear it and the noise was gone. Whew!!! I have a video of the sound but no way to put it on here. Crazy shit. Thanks for the videos Tony.

Sir, it is a pleasure to listen and learn your invaluable experience. Thank you!

Exhaust leaks can sound a lot like lifters or bottom end noises. I have a Honda B18 VTEC with very worn camshaft bearings. It sounds horrendous for the first 5 seconds when first started, like a cam belt idler bearing about to seize up, but gets quiet and runs smoothly enough as soon as the oil flow gets back to it. Another aspect is if the noise diminishes as the engine heats up. Solid lifter valvetrain or piston slap gets quieter as the engine gets hotter. Lifters and crank/rod bearing noises usually stay the same or get worse with heat. Exhaust leaks can be worse hot or cold and improve with the opposite temperature extreme depending on what is causing them. A mechanics stethoscope is useful, but a length of vacuum hose stuffed into an ear is also useful to find the general zone of a noise, especially useful to pinpoint position when it is a vacuum or exhaust leak.

Sometimes mechanical fuel pumps will sound just like a tapping lifter/valve... Also, I recently had one with what sounded like piston pin noise only on one cylinder, it was cylinder number seven that got quiet when I pulled the plug wire off that cylinder.

Don't forget the taxi issue, the good ole carbon knock that sounds like a rod knock. This was originally discovered in the old taxi cabs, since the cars never saw higher RPM's, the tops of the pistons would carbon up and produce a knocking sound. They used to trickle water or transmission fluid into the intake to clear them up.

Funny how right in the middle of you talking about lifter ticks, a ford commercial pops up. LOL I spit my coffee out laughing so hard

You didn't mention that the cam rotates at 1/2 crank speed so camshaft, lifter, rocker noises will be at a much slower rhythm than bottom end noises. Usually anything belt driven making noise will be very fast since the accessories are driven at 3+ times crank speed.

This is exactly what I needed. However it confirms worse than I hoped. Sounds like I need to pull my 440.. only 1500 miles and I have that loud tic when not under load (under load it disappears) Thank you very much uncle Tony for this ! Hello from Wisconsin

When you were explaining the flex plate deal you put me at ease in a lot of ways. My 300 i6 van makes a knock in gear but freely revving it sounds ok mostly, it's also super rhythmic. I've been thinking about the things it could be too much. I pulled the inpection cover to look, and I don't see anything out of place in the flex plate/converter area.

The wife's 'new,' 258 powered, accidental YJ exhibited the phone ringing under water last spring when I rescued it from its 17 year nap in the field. It ran, even with the bbd carb having been home to a family of mice for a few generations. That poor crank was worn almost .010" undersized and the mains were deep into the copper, though someone had patched it up with a new HV oil pump so it maintained decent pressure. The timing chain gave a pretty good song and dance when it revved too. I could feel the impacts with my fingers when I revved it. Haha. Good stuff Tony.

I bought a 78 cutlass for dirt cheap. It had a crazy knock noise. The guy thought he blew the engine up. He had changed the transmission. During the test drive, the car quit moving, and started making a knocking noise. He was stunned when I installed the flex plate bolts, and drove the car home.

back in the day i did a engine rebuild on a 75 vett SB , when the engine was reinstalled it had a tiny peck --tic-tic--and it kept getting louder and louder-- this was a super cheap rebuild and the owner didn't want new rod bolts so i was thinking the rod bolts were giving away-- so we pulled the mill out and it was a loose nut on the flywheel . we just tightened it up and put the motor back in. sounded just like a bad rod bearing or broken rod bolt.

I like your comment in the beginning about sounds that we like hearing like the big cam I have in my 327 Chevy small block that’s in my 79C 10 I love it how people think that it is missing and out of time till I whack at throttle and get past 35 and then it just goes to full scream mode

Finally I get THE info I've been looking for-low rpm tick and it goes away with torque but comes back with low load. Now if I can just find someone who can fix this truck for me. Thanks Tony!

I put my first clutch in backward. 1969 440 R/T. I had replaced the engine and added headers so I did not notice until the muffler shop was finished. Sounded like a rod until I pushed the clutch in. Tore it down rotated the clutch and drove it for years. Always check to see if the noise changes over RPM or load. Smart video.

That last part about steady state rpm then rolling into the throttle and watching the oil pressure gauge is extremely handy to know. I’ve witnessed engines do exactly that too. Be running at 40 psi then dip to 30 as you get on it before climbing back up.

Another way to differentiate piston pin/skirt noises from valve train noise is pull plug wire/ disable coil on the suspect cylinder, like tony said it changes load on that cylinder and if noise changes as you take away spark and put it back then you can be reasonably sure its the piston/pin and not a valvetrain noise.

Worked on a 5.0 mustang that had a bad balancer once. Sometimes the engine was smooth, sometimes it shook a little, sometimes it shook a bunch. We were looking things over when the guy worked with tried to shake the balancer and the outer ring came off in his hands. The rubber had detached so the outer ring would spin on startup. Sometimes it lined up well enough to not shake and sometimes it was way off. Was a pretty good outcome since it didn’t tear up anything else. Way better than one we had that broke a rod near the big end. That one luckily just had the piston stick at the top and didn’t really tear anything up. Just had a miss and vibration.

My 2006 Vibe made a BANG this morning... and that was all she wrote for movement, there went the transmission. My mechanic is trying to locate a replacement, with 450000km on it it doesn't owe me, but it's such a good battlewagon I want to keep it going...

Excessive carbon build up on top of the piston(s) due to low speed driving, high oil consumption can mimic a rod knocking sound because the piston is contacting the cylinder head. High clearance (usually due to high mileage)between the piston and cylinder wall also cause a specific knock which goes away usually when the engine warms up. That was typical in the early gen 3 6.0 V8 engines. It didnt hurt or damage the engine, due to the shorter deck pistons used and a wider clearance spec. Some even sounded like they were about to come apart. Pretty much the nature of the beast.. Thanks Tony for another great video, always get something out of that.

The phone ringing under water part describes my Chevy luv. I've always heard what I described as the glass bottle that doesn't instantly break in the return machine. When you hear it bouncing around in there.

My wife drives a ‘96 XJ. Thought I had a valve train noise. With a stethoscope I determined it was a worn out distributor. Noise varied by RPM because the center shaft was smacking around in there just enough. Never misfired. Smooth operation other than the noise. Replaced it and no noises. 280,000 miles.

I just finished a dingle-ball re-ring on the EFI 460 in my 95 F250. Only reason I pulled and tore it down was because it was burning a quart every 300 miles or so. It sounded great and pulled hard, oil burning was the only issue. I pulled it, tore it down, measured everything, reassembled and started it right up. Sounded good at first, but after a few minutes it started to rod knock once it warmed up. I shut it down and let it cool off. On second start up, it sounded great when cold but started to knock as it warmed up. It still idled quietly but knocked when revved. I took it for a short test drive and it seemed to be quiet when in motion, so I went on a bit further. It got nasty, so I stopped and gave it the "you wanna knock, I'll make you knock" treatment and revved it pretty hard. It started knocking at idle and then miraculously got quiet, both at idle and when revved. That lasted about 30 seconds before it knocked horribly, then shuddered, sputtered and then locked up solid. It would not crank, and still won't after letting it cool off for a few days. Oil pressure was good the whole time, and it didn't get hot. I'm blaming human error on reassembly. I think a rod cap has left the chat and the piston dropped across the crank throw, causing it to not rotate. Thoughts?

Back in the day ... I had a 1968 Dodge Dart GT with the 273 and auto. Developed a knock that had us thinking it was a rod. Being cheap I got a rebuilt 383 and dropped in it. (quite a story on that install) Turns out the noise was a cracked flex plate. :) Since the 60's I have developed an ear for engine/auto noises. That all got turned sideways 10 years ago when I moved onto a ranch that uses mostly Ford diesels. Their noises make my head swim. I have heard and worked on big block Chevy's with 12.5 compression that rattle less.

I dont know much about cars other than mine but I can recognize the engine very well.

I just had a noise that drove mad. It was a Factory 340 windage tray. It somehow did not like my magnum oil pan I put on my 1988 LA360 in my 80 D150 . I had the motor out and on the stand twice trying to find the noise. I was using a magnum pan because I like one piece oil pan gaskets, they are absolutely drip proof.It was thanksgiving and I could not locate any place the windage tray was hitting the crank . I left it out and solved my problem. By the way I had no issues with the windage tray and the old LA pan with the cork gaskets etc

The AMC 4.0 the only engine other than the 7.3 powerstroke that idles like a bag of hammers and likes it

Thrust knock on the Buick 3.8s along with that damper because the damper caused the thrust on the crank itself to wear. Replaced the crank and an SFI damper the low oil pressure and thumping stopped.

6:42 holy crap you just diagnosed my dad's old chevy truck we were both convinced had an engine problem

Good information.

Love it! Thanks Uncle Tony for the refresher! 👍

You said that right. Good lesson Uncle Tony!

Alpha...you crack me up....an "event". Still remember you doing the sign of the cross over the 5.7 in my 91 Formula pronouncing it dead in your garage on Katan when I rolled up with several spun several bearings. Good times!

Wow. You just described an old truck I had. Made racket when not under load. Sounded like lifters but would disappear under load, and at idle but when under reduced load like cruising at speed it would rattle like crazy and it was rhythmic, and was like that from having the engine built. I thought it was a valve train problem the whole time. I had the head pulled and worked and came and valves done and it never went away. I wish I knew but it ran like a scalded hound and forever and I finally sold it to a used dealer who hit me hard but never docked me for the engine. I probably put well over 80,000 miles on that truck.

Man I love this channel. Best movies on RU-vid.

Those 4.0 I6 Jeep engines are incredibly durable. There’s a video from the Neutral Drop guys that fired the front 2 cylinder rods through the block and it started right back up and kept going

All great advice, & Im pretty good at identifying engine noises. Though I was fooled on my way home one time in my 78 trans am 400/4spd. Thought I had a lifter going away, but ir was the back bolt on the ram air exhaust manifold had backed out a bit. Exhaust and lifter are speed sensitive but not load sensitive. Ty for all the great content & keep it coming!

My old van with a 318 sure fooled me when the engine management system was all screwed with because of so many sensors and other things gone bad. Not only did it run like crap, but it sounded bad with what sounded to me like internal knocking, but it kept on running. Then I worked off all the codes and all the smooth quiet power came back, and all the deep noises went away.

I have taken emery cloth to a journal to clean it up and put a oversized barring in with just taken the oil pan off . I worked at a used car lot back in the 1980`s. These were the ones we sold really cheap for cash or ran through the auction . I sold a Ford truck with a 352 engine like that to a guy who was the scrap parts man . I even told him what I did . He drove that truck for many years hauling scrap metal and parts .

To corroborate what Tony is saying, I bought a Honda at 105k miles that had piston slap. I drove it for another 125k miles that way. I eventually rebuilt, not because anything happened to the piston, but because it kept overheating under load. Basically, the piston lasted until the rest of the engine plum wore out.

Got one for ya Tony. 1983-318 D150/A999- 230k miles, runs excellent. After about 30 sec to a minute, knock from oil pan area that goes away after warming up...5 or 10 minutes, never happens again rest of the day...clueless. Only does it in the morning on a fresh start. Went through the engine last year, was an old farm truck, replaced everything (damper, chain, oil pump, water pump, fuel pump valve stem seals . Cleaned the pick-up of loose carbon chunks that were also in the lifter valley ( clogged heat crossover!). still has factory cam, pistons, rods, heads.New Stealth Intake with 1850 man choke. ESA delete for ecu/ballast set up with Spectra Premium CH04 dist. New y pipe, no cats & factory routing with single 2 1/2" glass pack. Besides the initial knock in the morning, motor runs & sounds excellent 24/7.

Also have a 96 Cherokee SE 4.0 240k miles... can't kill it, awesome engine. My old Comanche 4.0 blue a radiator hose, drove another 2 miles, parked at girlfriend's house. Next morning fired up like nothing happened...try that with a small block Chevy...lol !

Had one at a car meet a couple of years ago on an Aussie Valiant straight 6. Not the best environment to diagnose a knock, other engines running around you. It was very rythmic and consistent, no tools to speak of, I had my money on #6 small end, or broken piston skirt. Turned out to be a cracked flex plate, at the converter bolts. Later it all fell into place. The car had a transmission conversion, and in the process, the eccentric dowels weren't dialled in properly, which in turn, destroyed the replacement flex plate in almost no time too.

The crank pulley holes on my 455 Pontiac "egg shaped" from wear. It fooled me into thinking it was rod knocking until I was able to confirm the reason and replace it. Be sure to check crank pulley bolt holes. Especially if you drag race frequently.

I’m not holding out on your 4.0L blowing up. Ticks that don’t change with load, but do change with RPM could be a cracked exhaust manifold. Crack noises are not always easy to pin-point because everything is on the same side of the engine. But that’s the first thing I would look for on a 4.0L.

Another noise similar to rod knock at first listen is if the torque converter bolts were loose for a while and the flex plate holes get wollered, it does knock and rattle similarly to that of a rod

Excellent example of noises, I found that problem of the harmonic balancer where there was a noise like bottom end on a V6 Buick that comes to Australia in the VN commodore, thanks for the video, all the best to yous and your loved ones

I've got a 68 chevelle, 327. It's got a knock that follows rpm. Been chasing this thing for months. pulled valve covers, checked flywheel, checked distributor, replaced water pump, fuel pump, adjusted carb, checked brackets, tried MMO, tried a quart of ATF in the oil. i'm exhausted.

When the spring under the pump arm of a mechanical fuel pump breaks it sounds exactly like Rod Knock! Great relief to only replace the fuel pump! 👍

The only thing I would add Tony is that a wrist pin area will usually give you a double.knock

I had a buddy that thought he needed to rebuild his motor because of some bad sounds coming from it. Come to find out, the flex plate had a few cracks in it, and that was where all the noise came from. Motor was just fine.

Uncle Tony Love you man and especially the background noises from insects to compressor noises to background highway traffic

My Uncle had a 67 Chevy pickup with 283 2bbl three speed on the column. The main bearings were so worn that you would hear a deep almost sub sonic thump at idle. That thing never quit running. He traded it in on a new 77chevy van. Tough motor!

I had a bent crank in a 5 litre Ford pickup truck. It would run fine and didn't really make noise but there was a vibration at cruising speed and a slight hop at idle. The biggest problem was that the vibration caused my bell housing bolts to work themselves out! Until they worked out so far that it caused my flex plate to crack. I tried LockTite on all the bolts to no avail. I wound up replacing the flex plate/flywheel 3 times before I treaded it off. I think it was an 86 model but I don't remember. I bought it that way and only kept it for a few months.

A bad oil pickup tube o-ring in an LS engine may starve it of oil and cause rod knock. Cool video UTG.

Uncle Tony, I spent 15 bucks on eBay I got this thing that looks exactly like a doctor’s stethoscope but it has a very long metal probe at the patient end if you know what i mean and it goes to your ears in exactly the same way. It’s very good. If anything it’s too loud and hurts your ears…..!!!!

To listen for a rod knock. Under the hood raise engine to 1,000 RPM or so and let go of the accelerator so it gos back to idle speed. As soon as speed gos down you hear the thump thump thump of the rod.

I’ve owned a lot of Ducatis. Some had the dry multi plate clutch. It would rattle at idle in neutral. I got weird looks at stop lights but it was music to my ears.

I had a Chrysler 2.2 with a rod knock for 2.5 years and about 40k miles. It knocked like hell when I first got it and it knocked like hell when I sold it.

Hab a 428SCJ WITH A BOTTM END KNOCK . I pulled each plug wire and no charge because the windage tray had a slight bend so the rod bolt was chilling the tray . Also had a dip stick hitting the crank once and it sounded like a bad lifter so I straightened the tube and no more noises . This offbeat stuff can drive you nuts.

I also tell people that normally if its a tick most likely it a valve train issue or fan or belt. But a thump sound is normally a bottom end issue. Sounds can also travel. I have had a roaring sound from the front of a big truck but ended up being a wheel bearing on back axle.

Disorganized rattling noise in the front of the motor can often be the timing chain, either the guides are gone and chain slapping the cover, or the tensioner is doing weird things.

If this is only about "detrimental" engine sounds I don't think you missed much. I would have mentioned that an exhaust leak can sure sound exactly like a lifter "tick". But those aren't detrimental.

20+ yrs ago at a peterbuilt shop i where i was a mechanic , one mechanic rebuilt a trans for a whine . turned out to be a split hose off the turbo makin the whine !!

That 4.0 with the tick will probably outlive all of us regardless of the abuse its put through lol

Love it! I drive my Jeep the same way! Pet the Beagles for me!

Wow….that’s a lot to digest UT! Lol now I need a tutorial on causes of vibration in the drivetrain. Great stuff! Thanks!

I had a loud intermittent knock (worse under load and RPM dependent) on a 76 Cutlass with a fresh engine. Was sure it couldn’t be internal, so perhaps the flex plate…turns out three of the bell housing bolts had worked loose after ~3,000 miles! About 15 minutes of tightening and a world of anxiety was permanently relieved.

When you back off the gas (especially with a standard transmission) after cruising and the oil pressure momentarily increases a few psi, another tell tale sign the bottom end is loose. The engine braking effect does the opposite of UTG’s final example, punching it at 30mph

Good stuff Tony.... I got a knock in a 84 Silverado that sounds bad but I'll check that flywheel first since I have a trans issue with the 700R4 spewing trans fluid up and out of the dipstick.🤔🥴

pretty darn good. but you forgot the main bearings deep dull nock or the squeal of a fresh spun rod. also a stuck starter.

Great fun learning from you!

Dodge mini vans! I did so many of these I could have the trans out and on the ground in 20 to 30 minutes. 45 to 1 hr if I took my time. AWD what ever. They would usually come in with crank and cam timing codes. And a clank on start up. Got quite a few from other shops that shotguned cam and crank sensors at them. And wouldn't fix it. A scope and even a visual inspection with a small mirror would confirm the flex plate. Would sell a front pump seal and rear main seal too while the trans was out of the car.

I have an '87 XJ with a 4.0 that has that exact sound. It was there when I bought it 3 years ago. I'm dreading the day it finally gives up the ghost.

I got a new sound in my 302 windsor that gets louder the larger the load is on the engine and the rhythm is directly related to rpm. It did not have an oil issue but it did get hot from coolant leaking. Radiator was dry and highly pressurized when it happened. Been driving it for a year now and it's not gotten worse or gone away. No loss of power or fuel economy.

I've also had fuel Injectors mimic lifter noises as well.

Yep noises. My little cars engine has made a ticking sound since I bought it back on 1-5-07. It's a lifter and yeah it makes racket but has not affected this thing one bit. I have another lifter for but I have to pull the valve cover off and it don't leak/seak.

Thanks for taking the time to share this wisdom.

This video came at the perfect time. Just tore down my motor because of a suspected rod knock, turns out 3 of my pressed-in wristpins walked out within 50 miles, tore up the cylinder walls pretty bad. One forged piston is cracked but it held up!

When I picked up my 1990 Cherokee with the 4.0 I knew I'd be putting another engine in it. The guy sold it to me dirt cheap claiming it had a bad knock. It had sat for 6 years and holy cow, with a new battery started right up on ancient gas. Drove it 2 miles home the whole while sounding like a washing machine rolling down stairs.

Great video again. I recently did an oil change on my Toyota Matrix. After adding the oil I started it up to check for leaks. Immediately heard what I thought was an exhaust leak so I crawled up the car to check the flex joint. I figured the exhaust got jarred and broke the joint (the exhaust was Ok before I started). I checked the flex joint and then the donut ring, there were no exhaust coming from either one. I listed more closely and found the the sound was coming from the top of the engine, it turns out I left the oil cap off. I figured that I had excessive blow-by around one piston, I've haven't done any further follow-up to know for sure. I now have another check to do when I buy a used car.

My Chevy 4.3 makes all kinds of ratting and knocking sounds when it's cold, goes away after a few moments depending on the temp tho. Been doing it few years now. Still gonna send it. Haha

Put a transmission, I rebuilt myself, in a jeep wrangler. Made noice only in forward gears. Drove me nuts. Finally took It down the road. Ripped the cooler lines off. The fan was hitting the transmission cooler lines. I must have bent them just that little bit, changing it in and out.

I had a engine that i thought was knocking a rod. In fact i was convinced thats what it was. When we pulled the engine out it was the flex plate!