other blazer question

which motor, what year?

Whitelightning

I changed mine on my 91 S10 Blazer, 4.3, auto, 4x2 at 172K. It had some stretch in it, and replacing it did improve fuel mileage and she seemed to idle a bit smoother. Oh and you have a chain, not a belt.

As far as I know there is no mileage interval for recommended replacement, Ford used to recommend timing chain and gears at 50,000 miles, but that's going back 20 plus years. And ford chains always seemed to stretch worse than GMs did. that said, when a chain breaks, it scatters links through out the engine, so its a much easier to replace a chain, then pull oil pans, intakes and valve covers to fish out all pieces. The some earlier V-6 engines used a tensioner and guide and on those around a 100K miles.

Whitelightning