Got my Car & Driver issue today. Page 49 predicts an ATS-V with a twin-turbo V6 rated at 380-420 hp weighing in the neighborhood of 3,600 lbs. They have cost pegged at $55k to start.
I'd love to see it come in at, say, 435 hp (or more) and weigh a shade under 3,500 lbs just to rub C&D's nose into their bowl of sauerkraut.
Oh, btw, their rendition looks just Jimmy's photoshop slightly rotated. :D
1) The recall notice says, "... we have determined that under certain driving conditions, and with extended oil
change intervals, the timing chain could wear prematurely and cause the illumination of the
Service Engine Soon light. Timing chain wear can be affected by the age of the engine oil and
What We Will Do:
To ensure that your vehicle will not experience this condition, your GM
dealer will change the calibration of the engine control module, including the engine oil life
monitor, which in most cases will recommend more frequent oil changes.
2) On 3/7/11, RippyPartsDept (Chris) posted this:
"... the 3.6L engines ARE interference engines ... however that doesn't guarantee valve damage when a chain breaks
we have seen about 25% of the cars w/ broken chains not need any valve work
also, Mileage is not a factor at all in the OLM system - engine temp and RPM are the only variables (besides the type of engine since other variables in the algorithm are determined by the engine type)"
3) On 3/9/11, RAB posted this:
"My thoughts on this entire issue are:
1) I understand completely GM's thinking in their issuance of Bulletin 10287. Is has nothing to do with 'Customer Satisfaction' and everything to do with 'Cost Mitigation' for GM.
2) Warranty timing chain work on 2007-2009 HFV6 engines has cost GM a bundle. Changing ECM programming (i.e. upping the chain stretch threshold for when the Check Engine light is thrown) will have an immediate and huge downward effect on GM's further/future costs for this issue.
3) With a significantly increased amount of chain stretch now 'tolerated' by way of the re-programmed ECM, the point in time now at which the timing chain will become a show-stopping issue for many (the majority?) of owners of 2008-09 CTS's (i.e. problems of poor engine performance, engine misfire, timing chain breakage and potential for catastrophic engine damage) will more likely materialize shortly after the 5 year powertrain warranty expires. At that point in time of course the customer gets to pay the bill.
4) Further to item 3 above, to help ensure that the potential for a timing chain show-stopping issue is not made greater during the warranty period for reasons of a less-than-ideal oil condition (or an oil level that's less-than-ideal), the OLM parameters are revised to demand/encourage much more frequent oil changes.. at, of course, the cost of the customer (in the US).
5) GM's 2007-2009 HFV6 is found in the 2007-2009 GMC Acadia, Saturn Outlook, Cadillac CTS, Cadillac STS & Cadillac SRX as well as the 2009 Buick Enclave & Chevrolet Traverse. Only the Cadillac applications of GM's HFV6 engines get synthetic oil installed at the factory; all other non-Cadillac applications of the HFV6 engine get traditional mineral oil. With this in mind, it would appear that the use of synthetic oil in Cadillac applications provides nothing in the way of improved lubrication (vs. mineral oil) for the timing chain(s). It appears now that the OLM parameters in HFV6-equipped Cadillacs will more closely follow (duplicate?) the parameters set out for GM's non-Cadillac HFV6-equipped vehicles using mineral oil.
6) It appears, at least at this stage, that the re-design of GM's HFV6 engine (the 'LLT' and likely all other HFV6 engines) for model year 2010 effectively addressed the timing chain issue. I'm guessing the overall re-design involved quality improvements to the chain itself (manufacturing and/or material revisions), but more importantly, an improved system for the lubrication of the chain(s).
7) Anyone planning on keeping their 2008-09 CTS beyond GM's 5-year powertrain warranty period should give serious thought to purchasing an extended warranty.
8) The 'new GM' could have and should have handled this issue differently. They could have broken with the bad habits of the past and dispensed with the BS. Instead they continue to assume the majority of owners are idiots. It's pretty sad really."
4) On 5/5/11, RippyPartsDept (Chris) posted this:
"... it's my opinion that most of the timing chain problems are due to people always running low on oil (not checking the level periodically between oil changes)"
5) On 11/23/11, RippyPartsDept (Chrs) posted this:
"... the recall does shorten the oil change intervals but that's just part, the more important part is to recalibrate the tolerances for the chain stretching so the light will come on sooner than before to hopefully prevent catastrophic failure ..."
In summary, lots of bitchin' (some justified, but mostly irrational) and no absolutely clear resolution. It does, however, appear that a redesign in 2010 did something that may have improved the 3.6L motor so this will not be an issue in the future. This should be confirmed. Before Chris posted up his theory, I was already suspicious that low oil levels were a major contributing factor to the timing chain failures observed and that the 3.6 design itself was susceptible in this regard. Of course, that begs the question as to why there were low oil levels at all ... were the motors consuming the oil or was the OLM set too high by GM? But, if the motor was in fact redesigned and eliminated timing chains as a problem, the past is the past, and this is a moot point.
I've only read one thread (the one JimmyH linked to, above), but time permitting I might do a little more searching over the next few weeks to learn a little more about the redesign in 2010.
Doing a search, I found this thread on gminsidenews: http://www.gminsidenews.com/forums/f...26/index4.html
Here's another post from XXSS on 2/27/11:
"... I can speak from first hand experience that over 90% of the vehicles that land in my shop with P0008 current and require chains, also have low oil level (Most with none on the dipstick) and have traveled anywhere from 9000-20000kms between oil changes. The Camshaft actuators do require
oil pressure to function properly."
Apparently, GM went to a different timing chain/sprocket with smaller spacing in order to reduce noise, and that's what caused a problem. These chains may have been more susceptible to low oil/low oil pressure conditions.
Another search showed this link: http://gmpowertrain.ca/Product/3.6%2...%20Summary.pdf
Talks about the 3.6, but no mention of a change. It DOES, however, speak to the problem design (see bold print):
"2010 GM 3.6L V-6 VVT DI (LLT) 3.6L V-6 VVT DI (LLT) CAR and TRUCK ENGINE
− Base engine in the Buick Enclave, GMC Acadia, Chevrolet Traverse, Chevrolet Camaro,
and Cadillac STS.
− Optional engine for the Cadillac CTS, CTS Wagon, and Buick LaCrosse
− Advanced multi-outlet high pressure fuel injectors that inject fuel directly into
the combustion chamber
− Variable, high-pressure engine-driven fuel pump for multiple injection events
− Stainless steel fuel rail
− Advanced engine control module (ECM) for direct injection control
− RWD applications matched to 6L50 six-speed automatic transmission
− FWD applications matched to 6T75 six speed automatic transmission. It is an advanced
transmission with clutch-to-clutch shift operation for front- and all-wheel drive vehicles.
The transmission's six-gear configuration allows for a "steep" 4.48:1 first gear, which
helps deliver exceptional launch feel, and a 0.74:1 overdrive sixth gear. Sixth
gear lowers rpm at highway speeds, reducing noise and vibration while improving fuel
economy. Also, the 6T75 offers automatic grade braking, shift stabilization and precise
− New direct injection engine keeps oil life monitoring system
− Cam phasing coupled with direct injection further reduces cold start exhaust emissions
− Cast aluminum cylinder block and heads
− Double overhead cams with four valves per cylinder
− Cams driven by small-pitch, inverted tooth chain
− Variable valve timing with four-cam phasing for precise intake and exhaust tuning and
− High-power and high efficiency 11.3:1 compression ratio
− Cast aluminum polymer coated oil cooled pistons, with a fully floating wristpin
− Oil jets cool the pistons, while polymer-coated skirts reduce noise and friction
− Durable forged crankshaft, and precision sinter-forged connecting rods
− Cast aluminum structural oil pan stiffens the cylinder block structure and reduces noise
− Electronic throttle control with advanced integrated cruise control
− Reliable coil-on-spark-plug ignition
− Optimally tuned exhaust manifolds with close-coupled catalytic converters
− Composite camshaft covers are fully isolated and reduce noise
− Numerous other noise, vibration and harshness controls
− Exclusive durability enhancements and minimal maintenance requirements
− Manufacturing techniques refined for exceptional quality and manufacturing efficiency
Full Description of New and Updated Features
Base engine in Buick Enclave, GMC Acadia, Chevrolet Traverse, Cadillac STS, and Chevrolet
Camaro. Optional engine in Cadillac CTS, CTS Wagon, and Buick LaCrosse."
Here's a little bit more about a 3.6 redesign: http://media.gm.com/media/us/en/news/news_detail.brand_chevrolet.html/content/Pages/news/us/en/2011/Apr/0413_camaro_engine
Specifically: "Compared to the 3.6L V-6 in 2011 models, the new LFX engine features:
No mention here of a timing chain redesign, but this is 2012 compared to 2011 (supposedly after the 2010 redesign).
- New cylinder head design with integrated exhaust manifold
- Improved intake port design and larger intake valves within the cylinder heads
- Longer-duration intake camshafts
- Composite intake manifold
- New fuel pump and isolated fuel rail
- New, optimized-flow fuel injectors
- Structural front cover and cylinder block enhancements
- Stronger and lighter-weight connecting rods
- Camshaft cap and throttle body design enhancements."
Okay, I'm done.
Indeed. Time for Tylenol...
Nothing else going on today except watching snow showers and the wind.
Sorry. Got carried away.
Guys, any idea when the ATS-V is suppose to show up? Im getting conflicting reports from dealers. Id like to know if the ATS-V will show up before the 2nd Gen CTS-V production is ceased. Depending on how the ATS-V looks and what the powertrain is, I might just go for the CTS-V instead. Ive been eying the coupe for a couple years now, and even tho I want a light V, I sheepishly admit a V8 is just as important.
also note that 2007 V6 Cadillac, Acadia and Outlook engines have a warranty extension on them ('special coverage' is the terminology - i think it is 10yr 120,000miles)
it will reimburse you if you had to pay out of pocket for a timing chain repair - so i'm told
as far as I'm concerned the low oil levels due to longer intervals between oil changes are the biggest factor
(blame here lies both with owners for not checking and with GM for not having a low oil light/message)
i'd really like to know why a certain percentage of these engines seem to consume oil while the rest don't or barely do
on top of that there was a bad batch of timing chains - at least that's the 'rumor' i heard
(sht happens - not sure if this was ever proven or admitted to)
on top of that the sprockets/actuators have short teeth that allow a timing jump a lot easier
(i guess this was part of that engineering design to make them quiet - apparently a double edged sword)
anywho... back to our regularly scheduled thread topic