I don’t agree the 3.6 is junk whatsoever. I think it’s been a great engine for them. I’ve never seen one need a timing chain at 30k, 80-100k maybe if they aren’t maintained properly. I’ve also never seen a cracked block in one or even heard of that and I work on them everyday.
Oh, where do I start.
Let's see, I had a 2012 impala I bought new. I maintain flawlessly, mobil 1, long before oil life monitor told me..@ 30k, cracked block, they said casting flaw, coolant leaking into the cylinder. . tech at the time told me that this was a documented problem and gm engineering had developed a specific weirdo test to test for it and they know they have a few % of the blocks cast in this one place that have minor casting flaws that cuased issues.....Replaced engine. (shittyly I might add, car never drove right after they dropped the cradle) ... 20k later, that engine needed timing chains..stranding my wife and daugther in downtown saginaw mind you..., they did that, 15k later, needs timing chains again and I said you can take your f-ing engine and shove it and they bought the car back for over KBB value.
A friend had 2011 traverse. 3 sets of timing chains before 100kmi
another guy at work had 2010 cts, 2 sets of chains before he ditched that car.
another friend has 2013 impala, it's starting with the funny idle and they think it needs chains, he's just gonna sell it, still under warranty...any takers??
A neighbor has 2012 buick , 1 set of chains already with only 35k on it.
There is a very long documented history on the 3.6l DI and it's timing chain setup starting in 2006 first use in CTS. they have revised the timing chains at least 100 times and revised the block over 6 times, it's also what forced dexos oil on gm engines because the i4 ecotech had a similiar setup and also has a higher than is normal rate of chains going bad, techs will say full syn is best for the 3.6l, they also revised the software and oli life monitor a dozen times for shorter intervals.
Talking with tech's I know, the incidents of chains going bad seems to have subsided considerably staring with most 2014-15MY vehicles after they revised the block and chains yet again.... But they still go bad, just alot less. 2006-2009 are the worst years...I believe I read one article siting a GM source saying it was almost 50% incident rate go the chains going bad in those early years (of the ones under warranty..mind you..surely the rate goes way up as mileage goes up and warranty is gone)... Alot of dealers employ two dedicated techs on two shifts just to do timing chain jobs in the 3.6l. Go ahead, ask any GM dealer...go talk to the techs in the back, they'll tell you. They'll all have done countless 3.6l chain jobs and none of them are fun to do. It was a running joke according to one tech I know as to who was gonna get the short straw today and have to do the 3.6l chain jobs. I also do not see very many 3.6l equipped cars over 200kmi. just don't see them. I see a a shit ton of similiar vehicles with other engines, like the 3800 with well over 200kmi on them, 3.6l...not so much.
They knew it was a problem straight out of the gate, and in their defense most new engines will have some issues and most of the time they can be worked out and the engine goes on to have a happy long life (see 3800) . The chains just eluded them for years. They spent so much on development of the 3.6l they had no choice but to go all in and try to fix it. They've spent a wad on warranty work for these and there are class action lawsuits I'm not sure it ever paid off for them, except in lessons learned. I know it's their high value engine and they stuff it in damn near everything, and some of them are good, it seems it all depends on how well it was toleranced while being put together and alot of it was lack of oiling to the chains and low quality oil . But when you have incident rates anywhere near double digit % rates, and in this case it was well over that for a time at least...that is really really really bad.
From what I know.....the 3.6l is a total crapshoot at best and a pile of unreliable shit at worst.
