Last question, I promise....

kevinmach1 · November 1, 2005

What is the deal? I have a 2002 yukon xl with the 8100. On cold startup, the engine sounds horrible, which the dealership tells me is piston slap and that it's "normal".

Really, is it normal? I have a hard time believing that gm built this engine with piston slap being normal. I can almost believe that it doesn't hurt anything, it is queit once it warms up, but it is embarrasing that I have to tell everyone that walks by that it "normal".

What are we suppose to do, live with it? I have an extended warranty, but if its "normal", the warranty company won't cover it. Besides if its normal, I will still have it even if the replace the engine, right?

What do you think??? I am sure others have asked this before, so sorry to rehash anything.

Thanks...Kevin

GM-Tech · November 1, 2005

The cold start knock issue applies to 4.8L, 5.3L or 6.0L engines. I'm not aware of that issue on an 8.1. An 8.1 is a very rare engine around here, so I don't know if they have some similar issue, but there is no TSB on it like there is with the other engines.

kevinmach1 · November 1, 2005

Hmmmmm....Interesting....

05HD · November 2, 2005

I've seen a few 8.1s chew up rocker arms. Sounded a bit like piston slap but from the top of the engine. May indeed be piston slap though...

Sherlock · November 2, 2005

FWIW my 02 8.1 has piston slap on cold start. It has always had it and it goes away after a couple of blocks of driving. I use less oil at 36K than I did at 10K (now add a quart after about 3K miles and change the Mobil One at about 4K) and the engine is a Beast. I love it. When I recently had a transmission issue fixed under my extended warrantee they also checked out the engine very thoroughly and said everything tested perfectly. I quit worrying about the PS. Hope that helps a bit.

tim73 · April 18, 2006

My 03 8.1 has done it since I bought it. It had approx 56K on it when I bought it. It now has about 70K. I too swapped over to mobil 1. It also uses about a quart every 3000miles. However, here's a question for yall. I am assuming the oil is being burnt, as I have no leaks, this being said, I heard that synthetic oil will not hurt your catalytic converter like regular mineral oil will. This was told to me by my uncle, hes a service manage at a chrysler dealership.

I worried about it when I first bought it, but now not so much. As it is out of warranty now. Any thoughts?

dewfpo · April 19, 2006

Synthetic oil and Dino oil will have the exact SAME effect on your catalytic convertor.

DEWFPO

ChevyTech007 · April 19, 2006

Bottom line is that if it goes away after a couple of minutes, don't worry about it. Any synthetic is far superior to conventional.

Nappers · April 20, 2006

My 5.3 had horrible piston slap, sounded like the Chevy 6.2dsl . I run Mobil 1 and Wix filters and change every 5,000 miles and purrs like a kitten. towards the end of the 5,000 it will slap for like 1 1/2 seconds at start up.

Aaron

BurbanZ71 · April 20, 2006

I have heard some say a Seafoam treatment (top end + cleaner) will help reduce the clatter.

http://z71tahoe-suburban.com/iboard/index....&hl=piston+slap

496SS · October 18, 2006

I have heard some say a Seafoam treatment (top end + cleaner) will help reduce the clatter.

http://z71tahoe-suburban.com/iboard/index....&hl=piston+slap

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I bought my 01 new and it has never had any clatter. Has always used oil though. I also use Mobil 1 and AC filter and am thinking about switching to Royal Purple as I've heard it helps with less oil useage, or possibly something I read on here about puting a tube in the oil sucker on the bottom of the intake manifold.

TEE · October 18, 2006

My 04' Sierra w/5.3 did it when new but, seems to be pretty quiet at 36K

1999 Tahoe 4x4 · October 20, 2006

I feel for you. That would drive me nuts. I would write to GM and demand they do something about it. The 8.1 supposed to be the ultimate. But it does not sound like according to your description.