2007 Yukon Denali (84k) Temp Knocking Sound - Cold Start when Driving

[GM Customer Service]

gilbo,

I'm sorry; I am not showing any known "piston slap" issues within my resources for 2007 Yukon Denali vehicles. If you are experiencing this issue, I recommend having the vehicle inspected. If you need further assistance, please feel free to contact me privately with a description of your problem.

Louis
GM Customer Service

 

[Fast55]

Thanks for your views guys,

I'm on the fence, i'm by no means a mech, but do share your veiws. First, if i had spent a ton of money on a truck (new), I would want, no i'd expect perfection without compromise... And, with the world we live in, technologies in todays engineering should not produce these types of issues. But on the other hand, the amout of actual truck owners who had documented this sound since early, mid or later on in the engines mileage, who've then gone on to do 150-250k milage with no issues, reassures me this is not going to 'Grenade' on me. That said and done though, for such a fine looking SUV/Truck this sound on start up is annoying and i just want to ensure that my wife and me little sprog don't break down in the middle of nowhere.

I'm waiting on my wife to use a full tank at the moment (she drives does very little miles so i might have to use it up myself) then run the Lucas Deep Clean. If that doesn't work then i'm going to get GM to do the top enginer clean (and add Mobile 1 and decent filter).

With this results i'll report back on any changes in this.

Cheers - Polo

I'm not suggesting that yours will "grenade", especially if it didn't start until 80K+ miles. What I am suggesting to GM and Toyota, is that it does affect the vehicle's life and value, epsecially in the case of my Avalon. I've built enough motors and owned enough cars and trucks to know that the condition isn't good. There have been documented cases of broken pistons/rings in motors that have enough piston/wall clearance to cause the problem. My hope is that the Avalon DOES grenade while in warranty, because I think anyone that would buy the car from me the way it sits would have to be a complete idiot, transferable warranty or not. It's one of the worst cases I've heard.

To sit here and have anyone tell us there are no "known" piston slap issues with your particular vehicle is a slap (yes pun intended) in the face. Google is your friend.

Finally, I would not change to any synthetic this late in the truck's life. IMHO (and with some experience to back it up), you are inviting trouble in the form of increased oil consumption and/or leaks by switching now. You may have no issues at all, but it has happened, and reallly, the benefits of reduced wear and extended change intervals are mostly gone with half or more of the truck's life already used up.

 

[fire730]

It is complete ********. They know however, that it's highly unlikely the motor will grenade within the 100K powertrain warranty and even if it does, a short block will not cost them much more than paying a dealer to tear it down, bore it over, and put in new pistons. At least these are nowhere near as bad as the 3.5 in my Avalon. The damned thing sounds like a rod is about to come through the block until it's been running for at least 15 minutes, far past reaching what should be full operating temp. Needless to say, they're all done in my book.

That's the whole problem. If it will get them out of the power train warranty its not a problem. I had an 03 F150 with horrible piston slap. And of course it was normal and it started at 2k miles. I couldn't justify paying a note on it so I got rid of it at 18k miles.

 

[gilbo]

gilbo,

I'm sorry; I am not showing any known "piston slap" issues within my resources for 2007 Yukon Denali vehicles. If you are experiencing this issue, I recommend having the vehicle inspected. If you need further assistance, please feel free to contact me privately with a description of your problem.

Louis
GM Customer Service

what about say 2004-2006 tahoe/suburban/ yukon 5.3 ??????

 

[Polomintus]

Thanks Fast55,

I 'll take a rethink on the Full Synth then, i'm not overally bothered on the knocking sound on start up to be honest, just curious to the origin of it, but i'm going to have GM take a look at it at some point, may even have the Top Enginer Clean done to see if that does resolve the issue, if it doesn great, if not, we'll see.

I'll post on any updates as they come.

Cheers - Polo

 

[quattrotman]

gilbo,

I'm sorry; I am not showing any known "piston slap" issues within my resources for 2007 Yukon Denali vehicles.

Louis
GM Customer Service

You're joking right?

But seriously, to the OP, have you explored the possibility of an exhaust manifold leak? I had what I thought was piston slap too on my 07 escalade. Went in and dealer thought it was too. I had them look into it further and discovered a. Token exhaust manifold bolt. The noise it made sounded just like piston slap (had it before on an f-150) and it went away after it warmed up.

 

[Polomintus]

You're joking right?

But seriously, to the OP, have you explored the possibility of an exhaust manifold leak? I had what I thought was piston slap too on my 07 escalade. Went in and dealer thought it was too. I had them look into it further and discovered a. Token exhaust manifold bolt. The noise it made sounded just like piston slap (had it before on an f-150) and it went away after it warmed up.

Interesting, thanks Quattortman,

I'll keep that in mind, any other secondary side effects you noticed at all?

Cheers - Polo

 

[quattrotman]

Besides the knocking sound at idle, it chugged like a diesel when under load or going uphill. It lasted for max 10 min and the sounded completely normal. Actually drove me nuts for a while because I was so sure it was piston slap. Only reason I took it in was because my warranty was up and I wanted to see if they might fix it for free...turned out they did

 

[Sheriff]

You're joking right?

I find it extremely hard to believe that you spend the time to read

the replies from any of the GM representatives here in this forum.

 

[quattrotman]

I find it extremely hard to believe that you spend the time to read

the replies from any of the GM representatives here in this forum.

haha...I just couldn't leave it alone. It's funny, when I did that on the Caddy forums, everyone jumped on me for being so negative.
Love this forum