Yeah, which I found oddly comforting.Ilya wrote:Holy crap. Yeah, ours is nothing like that.
good news I hope for both of us.
Yeah, which I found oddly comforting.Ilya wrote:Holy crap. Yeah, ours is nothing like that.
Yeah, mine doesn't sound like that, at all. Whew! No such chirping, no random rattling. I get always the same steady noise, then it goes away in about 15 seconds.Ilya wrote:Holy crap. Yeah, ours is nothing like that.
For the record, that is DEFINITELY not the noise the chain makes. My guess would be somebody did chains on it and has the high pressure fuel pump timed a tooth off. That video is focused directly on the pump.Ilya wrote:Holy crap. Yeah, ours is nothing like that.
Well that would explain the black soot on the exhaust tips...yeah that bugs me so I keep a rag in my garage to wipe them off every day. Glad you shared this - thanks! However, at my 60K service, I will mention the timing chain TSB to the techs and get them to check it out as others have done, to document the visit in case it does develop into an issue later.BlackCat81 wrote:When you first start a fuel injected car cold, it runs in what's called open loop operation. That simply means it's not relying on any input from the air/fuel sensors to either richen or lean the fuel mixture. It operates on a pre programmed set of parameters until it switches to closed loop. Closed loop operation uses air fuel sensors, among other components, to determine the correct air fuel ratio and adjusts mixtures precisely based on the sensors voltage input. That's why when you start your car cold in the morning it always smells like it's running rich, partially because it's in open loop and partially because a cold engine requires more fuel. I've never monitored VVEL action in open loop, but that's my reasoning as to why it sounds weird for a few seconds when you first start it. Once everything starts jiving together, the car runs much cleaner and more smoothly.
If you're still under powertrain you're good to go. If it's a friend of a friend I'd hope he'd just go ahead and take care of them for you, I know that's what I'd do. Even if nothing is done, at least you had the issue documented while still in powertrain warranty so you'll have a case if it needs when it's no longer covered.
BlackCat81 wrote:I can't say for certain, but I think the noise has something to do with the high pressure fuel pump, VVT, and open loop operation during warmup. Once the car goes closed loop and is using the air fuel sensors to adjust the air fuel ratio, the motor smooths out and the noise goes away. The 5.6 is a noisy motor, and every one I've seen has the same noise.Deezyweezy wrote:The tech I talked to suggested a noise that occurs at cold start, then goes away in less than a minute "may" be unrelated to the timing chain. I love the car, day three of ownership, but man the timing chain has me puckered! I'll keep you posted on my results and certainly let me know what you guys have seen.
Ilya wrote:Does it sound like a supercharger whine? Might be an air leak near the intake?
Thx...I'll check it out.Ilya wrote:Might be a torn rubber boot or something connecting the intake pieces. This sometimes happens on some cars when you switch to CAI's, etc.
The transmissions can make a whine type noise under heavy/moderate acceleration too. Totally normal.Deezyweezy wrote:
BlackCat, thanks again for the great explanation on the startup noise, all indications are that you are absolutely spot on. One other question, I do get a high freq noise that occurs pretty much at every acceleration that was deemed "normal" during the drive test. I get the wonderful rumble of the engine but it has an absolute overlay sound that is present as I accelerate, especially if I'm really getting after it on an acceleration, but not present once I reach speed. The techs drove my car and said that they didn't hear anything that was abnormal for the M56x. They even had another guy who worked there and owned a M56x drive mine and he said nothing sounding unusual. Has that been your experience as well? When I listen to videos on-line I hear engine only...no "whine" if you will. Any idea what this "might" be related to or is this really just normal? The tech said the V8 isn't as refined as the higher production level V6's but I just want to ensure this isn't something...I'm going to have them check it again at 35K miles when my next oil change occurs I guess.
Thoughts?
Amen to that BlackCat! Love the car, absolute beast.BlackCat81 wrote:The transmissions can make a whine type noise under heavy/moderate acceleration too. Totally normal.Deezyweezy wrote:
BlackCat, thanks again for the great explanation on the startup noise, all indications are that you are absolutely spot on. One other question, I do get a high freq noise that occurs pretty much at every acceleration that was deemed "normal" during the drive test. I get the wonderful rumble of the engine but it has an absolute overlay sound that is present as I accelerate, especially if I'm really getting after it on an acceleration, but not present once I reach speed. The techs drove my car and said that they didn't hear anything that was abnormal for the M56x. They even had another guy who worked there and owned a M56x drive mine and he said nothing sounding unusual. Has that been your experience as well? When I listen to videos on-line I hear engine only...no "whine" if you will. Any idea what this "might" be related to or is this really just normal? The tech said the V8 isn't as refined as the higher production level V6's but I just want to ensure this isn't something...I'm going to have them check it again at 35K miles when my next oil change occurs I guess.
Thoughts?
I bought a trailblazer SS when they first came out in 06 and that trans whined like a spoiled brat on heavy acceleration. Just so happens to be in the design. I'd assume it's got to do with how something is shimmed or something to that effect.
All in all, I'm sure after reading through this thread everyone is now hyper sensitive to noises their cars are making. I can't stress enough how well built and reliable they are and to maybe take a step back, pop a cold beer, stare at it in all its glory for a bit, and keep on keepin' on.
The link of the QX56 that was posted. It doesn't sound anything like my car does on a cold start.Ilya wrote:Which link? There has been a few. If it's only 10-15 seconds, most people seem to think it's fine although some of us are trying to get the stuff replaced regardless for peace of mind. If it's the link of the rattling, etc. that lasts a lot longer, then yes...
You might want to ask this in the QX forum, but here's the parts for both M56 and QX56: