timing chain

[exploreco97]

Can anyone clarify when the timing chain should be replaced? 99 Alero 2.2 engine. Car has 101,000 on it. Runs good but our mechanic which we trust says to change the timing chain because if it breaks it will ruin the engine. I have searched the forums and some say that it should be replaced and some say that because it is a chain it never needs replaced? Please advise?

[maxwedge]

This is not a maintenance item, there is no changeover interval.

[jr6078]

As a general rule, timing chains don't "break". It's more likely that the chain could become sloppy, but most are equipped with tensioners to keep them tight on the gears as they wear. The only other likely scenario is that the one of the gears may wear and allow the chain to slip a tooth or two, which is enough to cause the car to run extremely rough or not at all, but not likely to cause engine damage unless you continue to drive the car with the slipped chain.

Either way, maxwedge is correct that this is not an item that is routinely replaced as with engines equipped with a timing belt, which is routinely replaced due to the possibility of breakage that could cause engine damage.

I wouldn't recommend replacement unless you're having a related problem or the engine is being taken apart for some other reason to the extent that replacing the timing chain is simply a matter of opportunity.