SOLVED 2.4l knocking on start up (video included)

(SOLVED see below)
I’ve tried searching all over TW and can’t seem to find a fix to my problem. Most threads on this topic died with no solutions.

I’m working on a 2004 2.4l 2wd automatic with 72k miles that has a really bad knock on start up. I did change the oil and there was no sludge or metal shavings. Looked normal. With my screwdriver stethoscope the noise seems to be up top in the front but it’s hard to tell. Noise clears up once you are driving and warmed up.

It sounds like timing chain slack but I find it hard to believe the chain has slack with only 72k miles. Is it possible the tensioner is bad causing it to have unnecessary slack? Any ideas?

Thanks in advance!

https://youtu.be/h4soKrlwFOs

 

Are you sure its not fan or ac clutch noise.....

my ac one makes a little noise in winter time for about half a minute.....

could be harmonic balancer going out.....how old is that one...
same on fan clutch....

when a harmonic balancer goes out it can cause a lot a damage around the oil pump and timing cover.........

 

eh, I don’t think it’s the ac clutch or fan. It’s pretty loud to be that but I’ll cross that off the list today. Sounds internal but again it’s hard to believe there is an internal issue at 72k miles.

 

Wanted to follow up on this. Nothing grinds my gears more than a post like this that the OP doesn’t tell us the result. Silver_Taco, you were correct! Harmonic Balancer had failed. Replaced and no more noise. Thanks!

 

Yeah there is a simple play book for these old dogs.....

There's about a dozen things we see over and over again.....
So I get lucky every once in a while.......

And for the $4x4's there is an additional dozen or so extra.......



Recently I'm getting a screech for a slit second at start.....
.....worries me the belt is slipping from the beginning of a wobble...

Really want to catch these early....they can do a lot a damage to the timing cover.....

Always watch for oil leaks after replacing one of these....
.....worse sernario.....loss of oil pressure if the oil pump has a crack around it....
thats what happened to mine....

 

I had a 2.7 in a 4Runner did that for years esp when was cold. Lasted 100000 miles still ran great when I sold it