Jimmy68

Some ADJUSTMENT. Ya. Chain jumped like mine did and the tech says ADJUSTMENT so he can charge extra.

Oldblue

Now, the 2010 and 11 would have VVT so a tooth jump could be the adjustment mentioned!

donbrew

Assuming that the jump went in the forward direction, you can force a reverse jump by rotating the crankshaft Counter-ClockWise. That is why you should NEVER turn the crankshaft CCW.

Bagpiper1

The chain skipped a tooth after installation of the tensioner, and the tech stated it should not have done that, so the mark for the timing chain was off to the camshaft gear, but just by one tooth. Not sure how they did it, but they took off the valve cover to do it. What stunned me was that they just charged $240.00, and no more than that for the whole job, which was good of them. And they showed me that everything was ok under the valve cover, did not hide anything. The service advisor told me that it is just a 1.5 hour job, and in the end charged me that. Just be forewarned that you may have to change the new tensioner as before, if you hear anything rattling in your engine. this is my point. It is not a permanent fix.

donbrew

Yep, I think if you read EVERY line in this thread you will find the same advice a couple of times.

The actual reason for the tensioner failure is that the chain has stretched farther than the tensioner can tension. Some can go farther than others.

RJ_RS_SS_350

Wait, first you said that the tensioner was from the factory, now you say the chain skipped a tooth after installation of the tensioner.

I'm probably misreading something, but it sounds like they(or was it someone else?) replaced the tensioner, probably without releasing it, causing it to jump a tooth, and then they charged you to fix it? And if indeed the chain did stretch, then this is going to happen again. Maybe you were so upset that you did not make your statement clear.

Bagpiper1

The original tensioner, is what caused the problem. I took it to get fixed once I heard a rattling in the front of the engine. They checked the chain, and it was very tight, as it should be. The tensioner is the redesigned unit, as my car is a 2010, and the tensioner was designed in 2009. I had the car towed, and they fixed it. They spent 5 hours on the car but only charged for 1.5 labor. The tech told me that on some ecotec engines, post 2009, She has found this problem. The catch is to catch in time, before the chain does break and / or stretch.

RJ_RS_SS_350

OK, thank you, I understand now. The 1.5 hours is how long the tensioner replacement should have taken. But they didn't quite do it right, causing the chain to jump. So they had to go back and fix their mistake at no charge. They did the right thing by you.

The fact that the tensioner failed is troubling. At only 90,000 miles none of the timing components should have failed. But occasionally they do, and you're right, there are no 'forever' parts. Great job catching it at the 'rattle' stage and getting it repaired immediately. I think what you also meant was that there was no check engine light until after the repair, to answer donbrew's earlier question.

I'm sure you're aware that the chain may have stretched some, so if you hear that rattle again, you know the timing set may need replacement at that time.

Bagpiper1

Yes, if I hear the rattle, I will turn the car off, and tow it to a auto shop. You need to do it, before major damage. But how many people really know to do this. The tech told me that I would not believe the damage, when people continue to drive a vehicle with a bad tensioner.

The tech told me she used to think that the chain would stretch, and damage nylon guides, and then metal bits would go in the oil as the chain bangs around , and then damage the tensioner where it locked.

Now, she has seen a few like mine, where the driver took the vehicle in immediately when a rattle was heard, and see that it is actually the tensioner, that is the first part to go bad( not the timing chain). She doubts that GM will do anything about it, as they will not be making the ecotec engine. Very honest people at this dealership.

So far, 1000 Km and no rattle, and no engine codes. I was lucky this time.

donbrew

I have opened up the timing cover on a car with about 100,000 miles on it. The guides where in tatters, everything else looked good.

I have seen a Cobalt engine where the chain ripped the oil spigot off and broke the boss that it bolts to. Everything under the timing cover was trashed.