I just got a “Customer Satisfaction Program” letter from GM stating that GM’s 3.6 liter V6 (the engine used in the Camaro, Saturn Outlook, LaCrosse, Cadillac CTS, and several other cars) is showing premature wear of the timing chain. A quick check of the web turns up that many who own this engine are experiencing troubles all the way up to the engine fragging.
GM is offering to “change the calibration of the engine control module, including the engine oil life monitor, which in most cases will recommed more frequent oil changes”.
Note that this language is intentionally vague, it only says that the changes include the oil life monitor, it doesn’t say what other changes they will make. I’m concerned that they might, for example, reduce the max RPM, or they might reduce the peak HP. So I’ve now written to GM twice asking them to list all changes that they will make. So far, almost a month later, GM has not responded to either one of my letters.
Does anyone else know what other changes GM is making to the “calibration”?
No car maker is going to state publicly anything more than what you’ve already been told.
It’s a lawsuit happy country anyway and none of them are going to provide any potential ammunition for a legal war. Intentionally vague is normal.
Odds are that this modification will not affect maximum RPMS, horsepower, or affect engine performance in any way and will simply remind the car owner to have the oil changed sooner than what was previously stated by the OLM.
The odds are that the new and improved update may still not be good enough for the real world and the oil may need to be changed more often than the new update will suggest.
What should be done is to forget that OLM even exists and base it on the odometer and time.
I read several posts on a CTS forum last week but saw no examples mentioned of engine failures. It seems that the cam position sensor was overly sensitive and was tripping the check engine light too soon and cam chains were being needlessly replaced. The cam position sensor will be recalibrated to trip the CEL later. The cam chain elongation figure that I recall seeing was very small, about 2 mm. Oil change frequency will be increased to reduce cam chain wear. Our 3.6 has gone over 12,000 miles which may be too much.
I suspect that if you do not drive your engine frequently to extremes, you would never see a problem without the recall. This information is early and therefore subject to change. Here is a little more info. http://www.enclaveforum.net/index.php?topic=7662.0
Just for comparison,lets say you bought a car that the manufacture claimed produced 300hp. You were somehow able to duplicate exactly the test method and conditions that the manufacture used (this is possible but not likely) and you ended up 25hp short, could you recover your loss?
I ask this because it seems you are on the path of saying “I bought this car because the manufacture made these engine output claims, now the manufacture must redude the engines output because it was not lasting long at the previous power levels”. (but it did make it out of warranty) Now you want compensated because you no longer have what you bought.There is some logic to the claim, but the manufacture can say “OK we leave your car alone,have a nice day”.
Sorry to stray from the subject, but:
Gee, does this mean the insanely long oil change intervals recommended by GM’s oil life monitor may be a bit off? And you may actually be better off changing the oil every 5,000 miles or so, as most everyone on here probably does?
This bulletin was first mentioned here in the Chevy Traverse thread if I remember correctly.
The part that puzzles me is what the OLM is going to start recommending after any modification.
If the OLM was spitting out 12k, 15k mile oil change intervals pre-modification does it mean that it will cough up 10k mile intervals post-mod?
In other words, improved but still not good enough.
Many of the old hands on this board including myself have been saying FORGET these “OCM” systems and change your oil every 3000-4000 miles and you can’t go wrong…
It’s nice to see a manufacturer admit that “extended” oil change intervals can drastically reduce engine life, causing key components to wear faster than planned…
Planned failure is supposed to occur AFTER the warranty runs out, not before!!
Now, lets talk about 0W-20 oil when you’re tooling across Arizona in July, engine oil temperature moving north of 300 degrees…Are you really, really sure 10w-30 might not be a better choice??
0-20 oil left in for 12,000 miles might not be such a good idea after all…
You can be sure that when we bring our 3.6 in I will have questions such as follows to present in writing to the service advisor with a cc to the new car salesperson if indicated:
- What is the before and after cam rotation CEL trip point in degrees of lost cam rotation relative to crank rotation due to cam chain wear or whatever measure is used?
- How was the oil change monitor countdown affected?
- Why is the oil change frequency a factor with this recall?
- Is cam chain wear more rapid initially to make a CEL trip somewhat likely and then does cam chain wear diminish as it might be when going through a break-in process or is it possible that a cam chain failure might be put off until a later date and mileage when the car is out of warranty?
- Has the need for this recall been exacerbated by people who often drive their cars aggressively such as using maximum acceleration from stoplights?
- Have cam chains broken or have they been changed only due to the CEL?
- What has GM done to newer models to eliminate this problem so I can know why I should buy again?
Back in the bad old days before computer engine management with associated cam event and other engine component monitoring capabilities, this situation would likely have gone unnoticed.
I miss pushrod engines, cheap to make, perfected over time, reliable and easy to repair. OHC engines are what consumers demand now or else a car maker will be accused of having an old fashioned design.
. I’m concerned that they might, for example, reduce the max RPM, or they might reduce the peak HP.
Peak HP for the 3.6L is 6300/6400 RPM depending upon application. The redline is 7000 RPM. Even if they knock the rev limter to 6500 RPM, the peak HP won’t change.
Nope. GM has been offering the OLM for almost 30 years and testing it a lot longer. OLMs have been reviewed by the technical community and were found to perform satisfactorily. Most manufacturers have OLMs now, and some (Honda, at least) no longer recommend an oil change interval. They say follow the OLM. This is old technology. Are you concerned that manufacturers now offer direct fuel injection that provides more power? How will direct injection affect your engine life?
“I miss pushrod engines, cheap to make, perfected over time, reliable and easy to repair. OHC engines are what consumers demand now or else a car maker will be accused of having an old fashioned design”.
I think it is a question of time before even simple push lawnmowers go to overhead cam engines. I was looking at lawnmowers yesterday since the mower I purchased in 1988 with a flat head 1 cylinder engine may be on its way out. All the new mowers had overhead valve engines. I suppose in a few years they will introduce overhead cam engines with belts that need to be replaced or the engines will self-destruct.
Techincally OHC engines are simpler than pushrod engines, fewer moving parts.
You are correct. I remember that even in the 1950s the Jaguar had an overhead cam engine. Sometime in the 1960s, Pontiac introduced an overhead cam engine on its 6 cylinder Tempest model and the engine was available on the Firebird. Most people, though, opted for the OHV V-8. As I remember, the Pontiac had a rubber “cog belt” as the timing belt was called back then.
In the meantime, I am going to try to get another year out of my simple flat head lawnmower engine.
The OHC engine does have fewer parts than the pushrod engine (just count the lack of pushrods) BUT the head(s) is/are more difficult to manufacture. I like the trade-off though.
OLMs have been reviewed by the technical community and were found to perform satisfactorily.
Define “satisfactorily.”
GM has a vested interest in keeping NEW car buyers happy. They also have an interest in meeting EPA emissions longevity requirements. Neither of these interests require that an engine have much useful life left after 100K mi or so (what is the emission requirement these days? 120K?)
As a buyer of USED cars (most of which are out of emissions warranty, BTW), I change oil more frequently than the OEM suggests because my interests are different from the OEM’s.
For 4 cyl engines, a pushrod setup is much less complicated that the 16 valve dohc balance shaft engines common today.
Sounds like they offering nothing except a recommendation to change the oil earlier.
Have they fixed any worn out chains. I cannot imagine a cheap endeavorer .
Chrysler’s Hemis, and GM’s small-block V8s and some V6s are still pushrod engines, and are still relevant, modern engines. Some may say the design is dated, but they are proven, reliable, and powerful.
My Lincoln has an OLM and it’s a feature I totally ignore even though it seems to seems to specify an oil change around 3500 to 4000 miles. I agree with you about 0, and even 5 weight, motor oil. Here in OK during the summertime that stuff runs out of containers just like water.
The oil of choice for me and my family members has always been 10W30 or 10W40 for winter and summer use. On an old high mileage beater they’ve been known to get 20W50 during the summers.
How many years did it take in order to make pushrods engines that actually were not only reliable and lasted a while.
Japanese have done a fine job making reliable and long lasting OHC engines that have many technical enhancements like variable valve timing. US makers are playing catch up and are relatively inexperienced.