Timing belt

First of all, there is no 24 valve 4 cylinder engine. It is a DOHC engine with 16 valves. It has a timing chain and I've only replace timing chains when they get noise or break. If your chain breaks a lot of engine damage will occur.

Jeff, I thought the same thing, 4 cylinders, with a 24 valve head?? Audi, and Ferrari made 5 valve heads, but never six!! I found that keeping to the manufacturer service recommendations, change oil every 5,000 miles, ensures a trouble free timing chain.