I believe this is piston slap. what do you think?

About four months ago I posted a video on YouTube of the sound I'm getting from the left side of my motor. originally I thought it was possibly a rod but I realize now it sounds more like piston slap. I don't hear it at startup only as it begins to warm and once the engine is fully warmed up while idling. after driving it and coming to a stop I don't hear it until it cools down again. I'm assuming this is because the expansion on the pistons when I'm running the engine under a load. Here the link bellow from YouTube. I haven't got any feedback yet. I was hoping to hear of others that have the same issue with their 4.0 liter engines to give me some peace of mind.
https://youtu.be/9RsNkuxnGxs

 

It looks cracked open, is that the cause?

 

No. the cat is completely sealed up. there are two halves of the heat shield that is separated only because they're two pieces. on the right side the heat shield is missing. It's definitely coming from the block on the left side it's hard to hear but if I listen closely at the wheel well I can hear the knocking sound. I also used a mechanics stethoscope later on and listened to the head it's coming from the center cylinder. As I mentioned, can't hear it at warm up only once the engine is at operating temperature when it's idling. once I've been driving and come to a stop and listen I don't hear it but as the motor cools within a minute it starts coming back again.

 

If it were the mythical "piston slap" then it would occur at the opposite times. It would be there when cold, not (or much less) when hot. That's something else.

For all you guys who jump on "piston slap", do you have any idea the clearances needed between the piston and the wall before you'd get that kind of noise? There would be so much blowby that you'd look like a crop duster.

 

Almost sounds like an exhaust leak to me. Could also be nothing/normal.

 

i have the same exact sound. doesnt do it as much on fresh oil...as oil wears down it gets more noticeable. i believe its piston slap also. i also do a lot of reading on it and saw the techs also say the same thing...maybe it is.......maybe it isnt....just going by what ive experienced

 

I have this too. 07 with 190K miles.

Runs good, isles smooth, doesn't burn oil. It's just a noisy engine. I'm not worried

 

I think it sounds fine honestly, i would call that commercially acceptable on behalf of Toyota





piston slap emanating from the cats though... that is a funny one

 

I've had both. Cold into hot. Mine was an enigma.

 

Which weight oil are you using? How many miles on the engine?

 

yeah techs said itll go the same amount of miles...bullet proof

 

Try some Lucas oil stabilizer. Helped my Chevy

 

The engine has 240,000 miles on it.
When I bought it it didn't make that sound at all. I actually listened very closely only because the motor has so many miles. I wanted to be absolutely certain that there was no abnormal sounds. three days after I bought it I change the oil and I noticed the sound. I think he had some type of additive in there trying to hide the sound.

 

What oil did you use?

 

I had piston slap in my old 22R-E. I had compression variance so I suspected it but was really able to verify when I rebuilt it just looking at the cylinder wall scuffing. It was much more obvious with a cold engine and probably because of worn rings. It was a pretty obvious tapping when I accelerated, didn't sound like the OP's video.

If I was to guess the clicking is the catalytic converter baffles starting to break apart or a mechanically sympathetic noise like a VSV or injector being amplified.

 

I would lean toward an exhaust leak. If the Taco runs good, it is probably not piston slap. An exhaust leak near the exhaust manifold can sound like an internal engine issue like piston slap, bad valve or even a bad rod.
I think everyone would like to hear what you find out. Wishing You the Best Outcome. Spock Out

 

When I changed the oil I went with full synthetic 5W 30. The previous owner said he used full synthetic oil in the truck when he bought it and he said the vehicle was meticulously maintained by the original owner when he bought it off of him at a 180,000 miles. I used an endoscope and went down inside the filler neck on the valve cover and I was pleasantly surprised to see how clean the internals were of the engine. Obviously I could only see the top of the head and timing chain galley. It is very possible that there's an exhaust leak at the manifold. This would make sense why it doesn't do it at startup but after it begins to warm I hear it. As I mentioned before if I've been driving the truck and come to a stop I don't hear it again until the motor has about a minute to cool down a bit then it comes back and I never hear it at any other RPMs only at idle and slightly above. I'm wondering too if it is something in the cat that is starting to break down. Thanks for chiming in guy! you gave me some different ideas of what that sound could be other than piston slap. I would hope that it's not piston slap but I have read that a lot of manufacturers run looser tolerances in order to gain MPGs to the point that piston slap is noticeable with some engines.

 

I used fully synthetic 5w 30 can't remember the brand. it was whatever was on sale at O'Reilly's at the time. About 200 miles ago I added a quart of Marvel Mystery Oil. They were calling for much colder temperatures for the rest of this month and going into next month...some single-digit and negative numbers they're predicting and I thought what could it hurt? it's high in detergents and may clean up the motor a bit and my also help at cranking for those cold morning starts. I know modern synthetic oils do flow at extremely low temperatures so additives are really not needed. I don't plan on keeping the Marvel oil in there for long. I have about 1900 miles on my oil and I figured I would drain it out in another couple hundred and put fresh back in to see if it changes the sound at all. I would suspect if it sounds exactly the same then it may be possibly something in the cat or a manifold leak but it's really strange that I did not hear that sound when I bought the vehicle and I really listen closely to that motor. I suspected he put some type of additive to cut the noise down.

 

Maybe when I get home from work today I'll make another video right after I jump out of the truck so you can hear the sound after driving and then record again in just a couple of minutes after the truck has cooled while idling to give you another video of how the sound comes back.

 

my truck has 60k miles. its definitely not an exhaust leak on my truck...exact same noise as yours.actually the best video showing and hear what it is yet!can clearly hear it