Topic: GM Timing Chain Issues on 3.6?

[sailor723]

I see a lot of stuff on the 'net about GM having issues with premature wear/stretching of timing chains on their 3.6.

Some sites seem to indicate it's mid 2007 on (do to a running change in part specs to lighter chain) some indicate it's mostly DI engines only....others say all 3.6's and still others say it is most prevalent in Cadillacs....others suggest it's common in Acadia's. As you can see there appears to be lots of different (and often conflicting info). The general theme seems to include suspicion that the GM OLM monitor is to blame by calling for too infrequent oil changes.

So....two questions

Does anyone know what the real story is on this situation?

What are the symptoms of this problem starting to develop? ....noise?....check engine light?...loss of power?

Here's an earlier post about the recall....

http://www.autos.ca/forum/index.php/topic,73243.0.html

[airbalancer]

give a look here http://www.acadiaforum.net , looks like a lot of members

A friend has one, no problems yet

[rrocket]

I see a lot of stuff on the 'net about GM having issues with premature wear/stretching of timing chains on their 3.6.

Some sites seem to indicate it's mid 2007 on (do to a running change in part specs to lighter chain) some indicate it's mostly DI engines only....others say all 3.6's and still others say it is most prevalent in Cadillacs....others suggest it's common in Acadia's. As you can see there appears to be lots of different (and often conflicting info). The general theme seems to include suspicion that the GM OLM monitor is to blame by calling for too infrequent oil changes.

So....two questions

Does anyone know what the real story is on this situation?

What are the symptoms of this problem starting to develop? ....noise?....check engine light?...loss of power?

Here's an earlier post about the recall....

http://www.autos.ca/forum/index.php/topic,73243.0.html

Personally, I find that part hard to believe.  Timing chains are pretty robust on their own...and the oil would have to be REALLY dirty...and I mean REALLY dirty (sludge?) to have any sort of degradation on a steel timing chain.

Though I'm not expert on the whole GM timing chain saga, so what do I know...

[articsteve]

What are the symptoms of this problem starting to develop? ....noise?....

I've had only 2 incidents with timing chains.

1.  On the GM 3.8 circa 1982 the sprockets were nylon if you can believe that and the chain would just reach a certain point and not turn.  Since it was not an interference motor no damage.  It just died on the spot.  The aftermarket already had a kit out for it and it was somewhere around $130.  The repair was easy.

2.  BMW 1.8   These motors had a design flaw.  Incorrectly tensioned?  I dunno.  But the sprockets ate the chain and the warning sign was a high pitched squeal type noise as revs went past 3000 rpm.  It took over 200k km or this to finally developed.  The parts alone were 1K.  I did this 2 winters ago on a car I was curbing.  The job was 10x harder than the Buick, but in contrast to most chain motors a breeze because I had huge amount of room to pull the the crank pulley off.

As for this GM 3.6; it could be just a weird design anomaly.  It will be friggin expensive to fix and no way GM is gonna own up to this.

[my2cents]

I read 3 pages of this interesting 16 page thread and skipped to the last post where someone said he just got a recall notice regarding this issue. That was March 3 2011 and nobody posted after that.

Check engine light at 25000 miles on an Outlook - Onstar diagnosed it as timing belt issue and they replaced all 3. Buick Enclave - same thing. Suzuki XL7 same engine - same problems.

http://www.gminsidenews.com/forums/f19/gm-3-6l-timing-chain-problems-99141/

[sailor723]

Yeah....and as far as I can tell all the "recall" involves is reprogramming the OLM so that it calls for a shorter interval between oil changes.

[Gardiner Westbound]

Carmakers have slashed vehicle maintenance requirements to mollify government eco-overseers and appeal to frugal consumers. Their prime concern is getting the car past the warranty period. Onboard oil life monitoring systems (OLM) may overstate oil change intervals. Oil changes maximize engine longevity and avoid warranty issues. They are cheap insurance. The time and money involved are insignificant, typically one additional $50 oil and filter change per year.

[articsteve]

I doubt very much it's a "clean" oil issue.  Zillion chain motors on the road with very poor oil change intervals.  This is going to be some sort of engineering issue whose cause will never be identified definitively.

[Winklovic]

A co-worker's 2005 3.6-powered CTS just went into the shop last Thursday.  Still waiting for the final word on damage, but there were aluminum pieces in the oil.

[rrocket]

I doubt very much it's a "clean" oil issue.  Zillion chain motors on the road with very poor oil change intervals.  This is going to be some sort of engineering issue whose cause will never be identified definitively.

I agree 100%.  I have my doubt the OLM let's the oil go so long that it could degrade a steel timing chain.  We're talking not changing the oil for YEARS.

[articsteve]

GM devotees should just face the facts that GM is still engineering sh*t.

Chain

[Erik]

GM devotees should just face the facts that GM is still engineering sh*t.

Chain

Still, huh?
And that engine came out in, what, 2003?

[articsteve]

hehe  Erik, didn't mean to post that unfinished.  Was going to qualify that "sh*t" statement.

Now I've forgotten what I was going to say. 

This is similar to the famous GM intake gasket issue.  It won't get dealt with.  They'll issue tweak after tweak and then eventually the motor will be discontinued.

Pre bankruptcy/post bankruptcy what's the difference in engineering?  The cars look better, but GM is all about marketing: incentives and volume.

[No H2O]

The cars look better, but GM is all about marketing.

And all you have to do is read "On a clear day, you can see GM". I wish I could find that paperback again.

I did a simple repair on a Corvette yesterday. I was very disappointed in the quality of assembly. I'll still take a 327 67 or a 70 LT1 though.

[rrocket]

The cars look better, but GM is all about marketing.

And all you have to do is read "On a clear day, you can see GM". I wish I could find that paperback again.

I did a simple repair on a Corvette yesterday. I was very disappointed in the quality of assembly. I'll still take a 327 67 or a 70 LT1 though.

What year Vette, and details of repair?

[Mike]

I'm not a GM basher, but the words 'wheel bearing' and 'warped rotors' still give me chills to this day.

Anyone know if these have been improved of late?  My alero and cobalt ss had these gremlins (as did my friends grand am, grand prix and just the bearings on his envoy)

[rrocket]

I'm not a GM basher, but the words 'wheel bearing' and 'warped rotors' still give me chills to this day.

Anyone know if these have been improved of late?  My alero and cobalt ss had these gremlins (as did my friends grand am, grand prix and just the bearings on his envoy)

7 (or so) wheels bearings on Trish's Alero went poop....

[No H2O]

What year Vette, and details of repair?

1993. I removed the window switches in the driver's door panel to repair them. I wasn't impressed as to how things went together. Many other things as well that I looked at; nothing seemed to fit or align very well. Lift the hood and everything is in the open. That I liked.

[No H2O]

7 (or so) wheels bearings on Trish's Alero went poop....

Same dealership? Could it be incorrect installation practices?

BTW, this is how easy it is to press a bearing into a hub if you heat the hub and freeze the bearing...

http://www.youtube.com/watch?v=7iqj3HytZMI

[rrocket]

What year Vette, and details of repair?

1993. I removed the window switches in the driver's door panel to repair them. I wasn't impressed as to how things went together. Many other things as well that I looked at; nothing seemed to fit or align very well. Lift the hood and everything is in the open. That I liked.

Except for the plugs!!  Have to go through the wheel wells to get one of them!