Strategies for Preventing Timing Chain Stretching (Wear): what can we do?

[Car_Almond]

Originally Posted by shrinkdoc

All this topping off and ridiculous frequent oil changing is pathetic for brand new car and is not a solution.

Agreed. And really, I think some evidence shows that frequent oil changes don't decrease wear on the chains. Sludge should be avoided by using the lowest-volatility synthetic available, Amsoil Signature 5w-30 or Pennzoil Ultra 5w-30, not avoided through frequent oil changes. Maybe, yes, an engine flush (like "Gunk Motor Flush" ) used every other oil change, to get rid of sludge.

[shrinkdoc]

Originally Posted by Car_Almond

Agreed. And really, I think some evidence shows that frequent oil changes don't decrease wear on the chains. Sludge should be avoided by using the lowest-volatility synthetic available, Amsoil Signature 5w-30 or Pennzoil Ultra 5w-30, not avoided through frequent oil changes. Maybe, yes, an engine flush (like "Gunk Motor Flush" ) used every other oil change, to get rid of sludge.

DFI is not a really good engine design if the drawback is generating oil sludge. If its a known sludge generator then perhaps the manual should state an engine flush every other oil change. But how many people will want to put up with that?

[Car_Almond]

Here is what I am thinking about doing, based on all the info presented above:

--Change the oil filter at each OLM flag.

--Change only half the engine oil at each OLM flag.

--Every 3rd oil change, put in an engine flush for 5 minutes prior to changing ALL the oil.

-- Use a Dimple magnetic drain plug to pull out iron particles smaller than 30 microns the oil filter missed.

-- Use an oil filter that mixes in glass fiber (with the basic cellulose-paper) into the media. Those are Mobil1 M1C-254, Bosch Premium 3474, NAPA Gold 7090, Fram TG8765, or Pennzoil Platinum HPZ-55, any to get out more particles like the silica/dirt/dust that comes in thru the air intacts past the rings.

--use any dexos1 full-synthetic, or for the brave: Pennzoil Ultra 5w-30 or Amsoil Signature Series 5w-30 **

** One other candidate oil is one formulated for another manufacturer's similar high-compression-direct-injection engines, Mazda's 0w-20 with high moly, a friction and wear component. We can bump up the viscosity just slightly by adding half quart of Mobil1 0w-40 available at walmart.

[Car_Almond]

Originally Posted by shrinkdoc

DFI is not a really good engine design if the drawback is generating oil sludge. If its a known sludge generator then perhaps the manual should state an engine flush every other oil change. But how many people will want to put up with that?

Direct Injection allows our LLT v6 to get 312 hp, high torque at low-rpm, allows the use of high compression due to charge cooling/atomization effects, and results in great fuel economy too, so its not bad.

Exasperating that GM won't come out with a real solution in my opinion. They won't because it woud embarass them, corporate economy too. And they won't even describe the changes made to the new chain in models made after July 15 2010.

For example, they could come out and offer magnetic drain plugs to lower wear from small iron particles, yet its too costly for them. Chain stretching would be reduced slightly from that alone. Or, they could ask us to use a full-synthetic dexos1 (instead of the synth-blend ones) to reduce sludge further, yet that goes against their corporate-wide rule to only require dexos1. And suddenly requiring an engine flush every 2nd or 3rd oil change would make them think they are asking too much of most consumers.... so everything is dumbed-down.

[shrinkdoc]

Originally Posted by Car_Almond

Exasperating that GM won't come out with a real solution in my opinion. They won't because it woud embarass them, corporate economy too. And they won't even describe the changes made to the new chain in models made after July 15 2010.

For example, they could come out and offer magnetic drain plugs to lower wear from small iron particles, yet its too costly for them. Chain stretching would be reduced slightly from that alone. Or, they could ask us to use a full-synthetic dexos1 (instead of the synth-blend ones) to reduce sludge further, yet that goes against their corporate-wide rule to only require dexos1. And suddenly requiring an engine flush every 2nd or 3rd oil change would make them think they are asking too much of most consumers.... so everything is dumbed-down.

I hate it when GM feels the need to pull a classic Toyota stunt. It will bite them in the ass in the long run.

[KMPrenger]

Originally Posted by Car_Almond

...
Exasperating that GM won't come out with a real solution in my opinion. They won't because it woud embarass them, corporate economy too. And they won't even describe the changes made to the new chain in models made after July 15 2010.
...

Curious, but what makes you think the chains were updated in these engines in July 2010? Everything I've read in the past was a guess that at some point the 2011 models got an updated chain, but nobody was 100% sure when.

Was that the start production date for 2011 models?

[Car_Almond]

Originally Posted by KMPrenger

Curious, but what makes you think the chains were updated in these engines in July 2010? Everything I've read in the past was a guess that at some point the 2011 models got an updated chain, but nobody was 100% sure when.

Was that the start production date for 2011 models?

I think it probably is the 2011 production date, not sure, but likely.

rtcat600man previously found this key info (with part numbers):
"Checked into this question, here is what I found.
12633451 and 12623452 were in production from 15July10 "

Interestingly, elsewhere on the web, there was an account of the Vauxhall service bulletin, which used the same 12633451 and 12623452 timing chains part numbers, on the V6 in Europe that is closely related to our LLT V6 here. Here is the basics of the bulletin:

Technical Service Bulletin 2895

Z28NEx - Timing chain elongation, SVS on, DTC P0016(1B) and P0018(1B) set in ECU

Insignia 2009 to 2009 - Vin 91000362 to 81145618 - A28NEH, A28NEL, A28NER, A28NET
Vectra C 2008+ - VIN 81000001+ - Z28NEH, Z28NEL, Z28NET

Complaint - Customer complain about SVS on, DTC P0016(1B) and P0018(1B) set in ECU. Further investigation reveals chain elongation.

Cause - Lack of robustness in the chain material properties aggravated by ages engine oil.

Production - Improved wear resistant timing chains (material improved and carbo-nitriding) introduced as of engine number HN 055 387 (29th Sep 2010)


Spare Parts: Part-Number: Catalogue-Number:

Primary timing chain 12633451 06 36 246
Secondary timing chain (2x) 12633452 06 36 249

[Car_Almond]

Note the Technical Service Bulletin 2895 (a TSB, not a recall by the way...) is for a similar GM V6, the LP9 on the Saab 9-3 and 9-5, Opel Insignia, Vectra, .. Europe models etc., and the bulletin appears to address the same problems as we have seen many times in North America on Cadillacs, GMC, Chevrolets that use our High Feature V6. Anyway, another clue.

Its a materials problem aggravated by aged engine oil, as the TSB above says.

[jkchambless]

Originally Posted by Car_Almond

jkchambless, is that a 2010 Camaro that lost the timing chain? I guess the new chains are somehow better, probably carbonitriding, not sure.

Yes, early build (may/june) 2009.

[philthy]

My timing chains were just replaced under warranty. It was a pre-production order (R6P) very early build...took delivery May 14, 2009. It had just shy of 38,000 miles when they went bad.

[shrinkdoc]

Originally Posted by jkchambless

Yes, early build (may/june) 2010.

Not sure about the 2012s but quite a few 2011s have had chain issues too. Not sure of the build dates though. Got my 2011 in the second week of Feb 2011 with a build date the first week in Feb. I hope I am safe.

[TooCool5]

Originally Posted by philthy

My timing chains were just replaced under warranty. It was a pre-production order (R6P) very early build...took delivery May 14, 2009. It had just shy of 38,000 miles when they went bad.

Wow that is low miles for a failure. I hope my chains last, I won't have 35k
on my car in 5 yrs time.
There goes the warranty.....

If not I'll have to bite the bullet like PieNsky did and tear it down. This is not an easy job.
I sure as heck will not be happy with GM but I knew I bought a first yr car with an aluminum Cadillac engine.
Need I say more? With all the CTS chain problems GM continues to produce the same crap.

[Car_Almond]

.
If not I'll have to bite the bullet like PieNsky did and tear it down. This is not an easy job.
I sure as heck will not be happy with GM but I knew I bought a first yr car with an aluminum Cadillac engine.
Need I say more? With all the CTS chain problems GM continues to produce the same crap.

One might think the LLT was proven with those years in Cadillacs, Opels, Acadias, etc. Sounds like GM had a chain supplier vendor that forgot to surface-harden or carbonitride, whatever metallurgy required, some of the production chains. Bad materials on some.

Considering putting in ZDDP additive. I hate adding stuff to oil, yet want a little extra protection on those metal surfaces inside the chain. Maybe it won't hurt to put a little in. Not too much though. Carefully look at bottle recommendations and go half of that to be sure I don't overdo it and cause chemical issues with Pennzoil in there.

[PieNsky]

Originally Posted by TooCool5

Wow that is low miles for a failure. I hope my chains last, I won't have 35k
on my car in 5 yrs time.
There goes the warranty.....




If not I'll have to bite the bullet like PieNsky did and tear it down. This is not an easy job.
I sure as heck will not be happy with GM but I knew I bought a first yr car with an aluminum Cadillac engine.
Need I say more? With all the CTS chain problems GM continues to produce the same crap.

I just wish my hard drive on my old computer hadn't crashed. I videoed the tear down and how to line up the chains. FWIW, it is really not too bad a job, just around 90 bolts to remove. Mine was also a RP6 with a June 26 pickup. I got a download from ebay of the tech manual, watched a three part set from youtube of a Cadillac 3.6 timing chain replacement. It is very close to what we have with the exception that we don't have that one difficult bolt to remove that the Caddy has. You do have to buy the cam tools to hold it all in place.
https://www.google.com/#q=cadillac+3...chain+problems