04 Engine surging and rough idle

[aveostein]

There is a plastic idler wheel in the timing belt loop - the wheel recently shattered on our 2004 Aveo causing the timing belt to lose tension and crashing every valve! I would have the mechanic replace every pulley, tensioner and wheel in timing loop!

When you replace the belt, you replace everything. The idler, belt, and water pump.

[tringoldsby]

When you replace the belt, you replace everything. The idler, belt, and water pump.

Yes - definitely replace *everything*. In the case of our idler, the bearing was perfect (even after it shattered) so it hadn't given any concern during the previous timing belt change (40,000 KM = 25,000 miles before). I had never anticipated the actual plastic wheel would disintegrate!

If there is a weak point to the early Aveos, it is the timing assembly. The Aveo has the shortest timing belt change interval of any car I've ever seen and they aren't kidding!

So, change anything and everything in the vicinity of the belt that could possibly cause a belt failure. I really question the engineer's decision to make it an interference engine. Sure, you get a couple of extra HP and perhaps a trifle better fuel economy - but the cost of a broken belt outweighs any possible gains.

[tringoldsby]

I should mention, there is a tensioner and an idler, IIRC.