tensioner pulley broke but timing belt still intacted, question on motor???

**ShaunS.** · 03-02-2012, 02:55 PM

hey everyone, i have a standard 2005 chevy aveo ls, the other day i was going down the highway (70mph) when i heard a grinding noise and my car died, after having it towed home and checked out i was told it was the starter so i replaced it, didnt start, we thought maybe it jumped timing so as we were checking it we noticed the tensioner pulley was snapped in half but the timing belt wasnt broke and it did not jump timing, i know these have the interference engine so im a bit concerned on the damage that may have been done, does the tensioner pulley cause major damage when it breaks? i know what could possibly happen when the timing belt goes. has anyone had this happen before? this is our only car other than my 71 chevelle but thats not much of a winter car haha!

**daug1502** · 03-03-2012, 05:15 AM

Check your valves. IF the tensioner snapped then the belt probably wasn't staying where it belonged either. I would treat the car as though the belt snapped anyway, and diagnose from there.

**thehunterooo** · 03-03-2012, 08:35 AM

+1 on checking the valves, and I would replace the timing belt and all pulleys anyways while you are at it, a good mechanic or yourself can have it all done in a day so it can be back on the road.

**petrified.rabbit** · 03-03-2012, 02:01 PM

tensioners cause the belt to fail almost as often as the belt failing on its own.

your easiest solution to this is to fix the tensioner and timing belt (do it all, water pump too), and see if it runs. give it a compression or cylinder leak down test, to see if the valves were damaged.

**ShaunS.** · 03-04-2012, 12:48 AM

after looking at a diagram of the timing belt assembly i notice that it is not the tensioner pulley that broke but it was the plastic idler pulley, can this do just as much damage to the motor? little concerned since i was doing 70mpg on the highway.

**petrified.rabbit** · 03-04-2012, 04:46 AM

its about the same concern, same solution.

**NYChevoo** · 03-04-2012, 11:20 PM

+1 on that petrified.rabbit!

**Aveowego** · 03-07-2012, 06:41 PM

I guess my question would have to be how do you know the belt didn't jump time if the tensioner broke? I would almost have to assume if the tensioner broke the crank spun the excess out. I've never seen it happen on an aveo motor yet. I have seen it on other 4's though and I would say, expect the worst. The grinding noise is usually you cam spinning free knocking the valves against the pistons or each other, and sometimes chewing the lobes off the cam or at least eating chunks out of it. I am for your sake and wallet hoping that's not the case. Make sure to go through petrifieds list. and while you've got the valve cover off, look for loose metal or anything bent, broken, chipped, warped, or knicked. I pulled the valve cover off my friends talon after a tensioner break. We managed to save the block luckily. The head didn't make it.