I was told by another Denali owner that the 2001 & 2002 Denali engines were defective. He stated that there is a piston problem and at start up the engine sounds like a diesel engine. Anyone here have this problem? This guy got a new engine from GMC at no charge. You would think that this would be a recall item, but again if this is really a legit problem that would be a lot of engines and money for GMC to fork out. I'm taking mine in to the same dealership this guy took his to and get mine diagnosed. We'll see?!

Piston problem?

On all 2001-2002 Denali engines...that's unheard of. GMC would definately ensure that all customers be notified of such a problem. Because this was never stated by GMC or any GM affliate that this is a problem and recalls were not issued I would not worry. This may be a problem to one particular driver and not all.

Jon

Originally posted by mandirigma01
I'm taking mine in to the same dealership this guy took his to and get mine diagnosed.
Any updates on this? The 5.3 engine is known by many owners to sound like a diesel on start-up, and GM is known to deny it repeatedly.

Others have stated on this forum that this is totally normal. This "diesel" noise occurs when you first start up the engine. The noise disappears within a couple of seconds. I was told that this does not affect engine performance by GMC. There are no plans for a recall.

A recall is for saftey items! Engine knock noise will not result in injury or death so no recall will ever be issued!

GM's statement on this as of 3-18-2003 is and I quote
"Some of the above vehicles may exhibit an engine knock noise that begins in the first 19,000-24,000 km (12,000-15,000 mi) of use. The knock noise is most often noticed during initial start-up and typically disappears within the first 5-30 seconds (may last longer in extreme cold temperatures). The noise is usually more noticeable on the initial start-up when the temperature is below 10°C (50°F) and may be more pronounced on the first cold start following a long trip.

This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall. GM Powertrain Engineering, and an analysis of engines with this condition, has confirmed that the noise is not detrimental to the performance, reliability or durability of the engine. THIS NOISE DOES NOT HAVE ANY EFFECT ON THE LONGEVITY OF ANY OF THE ENGINE COMPONENTS.


Important
At this time, attempts to repair this condition by replacing the engine assembly or pistons are not recommended."

I have a 2002 Yukon with 25K miles on it and it has been making this noise. I have had it checked by the dealer and they gave me a printout of the statement that was noted earlier in this chat thread. However, the noise has not been going away after the engine warms up. GM states that the noise usually goes away a couple of minutes after startup, but I have found that that is not the case. It is a really bad sounding noise for a gas engine to make and even noticeable by individuals with little or no automotive mechanical aptitude who even make a statement that "something sounds wrong".

Originally posted by Flatrater
GM's statement on this as of 3-18-2003 is and I quote...
I would have more respect for GM mechanics had they shown me this document instead of treating me like a dumbass child.

Any way I can get a copy of the original document, so I have something to show the next owner of the vehicle when they ask about the noise?

Hello, I thought that the Denali's have the 6.0 liter engine like my Yukon XL K2500, and not the 5.3 liter engine like the Yukon K1500?
I had a 95 Suburban with the 5.7 liter engine that would do the same thing, especially under acceleration. It would settle after some time. That was not much fun, I was waiting for a rod to come through...
This is "normal" for a lot of GM 5.7 liter engines as per GM. Not in my book!
Take care, Eggert :bananasmi

Hey guys! here's all you want to know and more about GM's known piston slap problem.

http://www.pistonslap.com

edit: As far as I know, the only engines affected are 1999-2003 (2004?) 3.1, 3.4, 4.3, 4.6 (Northstar), 4.8, 5.3, 5.7(LS1), 6.0 or 8.1 liter engine And yes, the 01 and later denalis do have the 6.0's :D

Oh no - a web site dedicated to the dreaded piston slap?!? :)

I don't want to go off on a rant, but I'm always amazed at how many dealer service departments neglect/refuse/whatever to reference TSB's when trying to diagnose a problem. With my Denali I've caught my "service advisor" on this twice now. First with this issue and second with the headlight flicker/stabilitrack issue.

Take care,
Jerry