Has anyone here had their 3.6 timing chain go bad? Its a pretty widespread engine across all of GM's divisions, so if it was as bad as the Northstar's head gaskets, it could certainly be a major issue for owners.
Anyone in service/parts have an estimate on the frequency of failures?
Some third party info:
I have done probably 5 or 6 sets of the chains at work. SOme of the other techs have done 15 to 20 of them. They do have a supplier issue and every chain i have taken off has been very stretched. They are kinda of intimidating the first set you do but after that I realized they are not that bad to do. THey do have special tools though to do the job. Cam holding plates are needed. The timing has to be set in a 2 stage process. Oh and there are actually 3 chains....one to each head and a primary chain that connects them and the crank. sounds confusing but not really. the front cover does need to come off and everything that is on the front cover. the lowest milage i have seen so far is 7,200 miles. I have done 2 cts and 2 srx and 1 dts. all under 25,000 miles. they also have cam postion actuator issues too. you have to measure cam end play and install shims as needed behind the actuators depending which manufacturer actuators are on the car. delphi or asin. i have done quite a few of them as well. We also have had them come in with a p0018 and p0008 which usually go along with the timing chain issue....but a few times more rare occations we had to replace the crank shafts for the engine correlation concern. there is actaually a bullitine on this. the reluctor wheel on the crankshaft which is press fit spins some on the crank and you have to replace as one unit.
From what I've been reading for the past week, 2005-2007 are the years affected. Anything 2008 and newer should be fine. And because the chains break/stretch early in the life of the vehicle, used cars coming out of the factory warranty period should be okay.
Failure in later models? Did GM continue to use the bad batch of chains until they were depleted?
good luck. We have lambda vehicles in the shop on a daily basis for timing chain issues. they range from every year in production - 07-11. seems to be more common on vehicles that go long distances between oil changes. regardless of what GM, dealer, oil life monitor system says, make sure to change the oil every 3000 miles. DO NOT go off what the oil life system says or anyone else.
You wont know there is an issue, until the check engine light comes on. it could be something else, but typically this is what the issue is. they will throw codes for camshaft/crankshaft correlation, etc. several bulletins addressing the issues.
also mileage doesnt matter. we see them with 4000 miles and up, all with same problems. typical issue with the boat anchor 3.6 liter.