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

Thanks for the info. I bought a cheap chinese timing belt and it failed after 3000 miles. Now enging is knocking after repairing the top end. Will drive until engine goes kaput. Noise is not that bad.

i bought today a new 318 magnum engine because mine old engine was making realy bad knoking noise at high revs and also when i drive up the mauntians the rod knocks realy bad

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.

If you suspect a rod knock why don't just remove the oil pan and get there visually right away ?

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.

I'm not sure I can remember a time when our 01 Jeep (bought new in 01) hasn't made a ticking, knocking, or whatever you want to call it noise. Northeast rust is going to take it off the road before the motor goes. We're trying to keep it on the road.

Hi Uncle Tony My name is John up here in Boston I have a quick question to ask you I have 3418915-f cylinder heads for small block Mopar what does the f mean and are they good heads

Would that make your engine tough to rotate over

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 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.

You may have run across this in the past, I did personally. A chunk of carbon broke free in a cylinder after a cold starting backfire. Sounded just like a rod rap. I have a good story about that incident, but it's too long to tell here.

Pin noise (on the ones I have seen) tends to go away as the engine warms up. One more reason to not buy a car with a warm engine.

Determining if a bottom end is loose based on the oil pressure drop then rise is an awesome tip.

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.

My xj was torque converter bolts. Unfortunately the torque converter bolts hoged out the flext plate an pushed the crank forward so hard it seized the engine.

I’ve got a ticky knock sound that starts when revved up, only while cold, speeds up with Rpm, and goes away if restarted, or after it gets a little warmer. My theory is that it’s a piston/bore tolerance issue that goes away when the metal heats and expands. 2000 Ford 4.2 V6 for anyone curious

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.

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!

How about piston slap? How do you determine that noise?

A bad piston pin will generally change as the engine warms up

Best way I found to isolate rod knock is to remove spark plug wires one at a time. When you pull the wire off the bad rod the noise will definitely change

Can you tell us about the constant whine coming from the passengers seat whenever my wife is in the car with me?

You keep playing with jeep engine, it's going to let you down some place you don't wamma be!

That’s what I did today. Replace my flywheel. It made a ka-chunk sound at start up. Other times it started fine with no sound. Then it broke for good on the highway and I had to get it towed.

Cold engine knock

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?

Funny story. Bad noise. Cranks a'nockin'. It's my new girlfriend's car. What did I do? I was trying to get home. Not in a race, just trying not to get arrested. 1978 Oldsmobile Cutlass. 255? Kapow!!! Something broke, it just started KNOCKING. I fixed it. Clue is, kind of an H shape. It took me two weeks to' figger it out. When I took the lid off the air cleaner, I lost an eyebrow.

great descriptions of the different sounds, spot on !

Had a pinto we had a spare engine had a knock we were gonna just run it till it quit one day car idling wouldn't move shut it off wouldn't start .the flex plate broke in a circle in the center . Ps those dampers on 3800quite common 🤔

I had a pice of carbon that came off the top of a pistons and it sounds like a rod nock!

Motor go brrrrrrrrr

Got a knock but can't tell if it is a rod or main. Old mechanics trick. Pull the car up to a tree and put it under a load by giving it a bit of gas. If it is a main, the knock will disappear. If it is a rod, it will still have the knock

Exhaust leaks like on the new Hemi trucks.

Have you ever seen a slant 6 with a badly worn timing chain so bad the it would rattle (on the cover) while driving in a particular direction, like say a curve at road speed?
Produces a rattle at speed, while turning in a particular direction.

wish i knew about rod knocks before i got my last used car. Luckily I unloaded it as a cheapie trade-in before it got too bad.

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

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!

Low oil pressure is a sign of bottom end engine wear

Taking notes here; my 8.8L Ford has a ticking on top

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.

1989

ran marvel mystery oil for a while

buick 350 repaced rings and rod and main bearings and still had tick until the end , piston departed from rod . I never thought about that when rebuilding

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

A lot of Isuzu v6's got scrapped for a rod knock that was really just a bad timing belt tensioner.
If the knock goes away over 2500 rpm, it's the tensioner.

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.

You're a cool old school mechanic" fun to watch you. and learn we all have a part in this mechanic Society to teach each other regardless of age, I'm Generation X on between the Baby Boomers and the millennials God help my generation x

Let's give some credit to Click and Clack. I loved that show.