What are the telltale signs of a timing chain that needs replacement? My car has 147k miles, no reduction in mpg (objectively, 24.9mpg) or performance/driveablilty (subjective).

 

I didnt think timing chains ever NEEDED to be replaced

 

normally they dont need changed but there are cases where they will go bad, its rare but it happens.

 

I had a nissan 240sx that had 240K miles before it died, and it wasn't because of a timing chain. I know of another 240sx that has 233 K and is still running strong.

I think they never go bad. Something else is bound to break before the timing chain does.

 

the chain does not wear out. what wears out normally are the guides and rails for the chain along with the sprokets due to lack of oil. most people who don't know much claim that as chain failure because normally when something like that happens people get new chains as well since they are removing everything to get access to the guides, it makes no sense not to replace it. and timing chains are what people know like spark plug.

A sign of chain failure would be a CEL saying your cam shaft sensor being bad. A rattle in the timing case. stuff like that.

 

your chain is either good or bad good meaning intact or bad meaning broken

 

This is what I was always told