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sms
04-13-2004, 09:43 AM
The Yukon is gettin' a little help here. After about 6 months of dialog with the dealer about a cold start knock (aka piston slap)
We got scheduled for the new and improved piston design.

sms
04-13-2004, 09:43 AM
block

sms
04-13-2004, 09:44 AM
p&r, old design. Note how short the skirt is in an effort to reduce weight. It works great in hand built test engines, but in mass production the bore to piston clearances were to variable. The '03 model year pistons have longer skirts and a coating. Good news, the cyls are round and not beat up from the slapping pistons.

sms
04-13-2004, 09:56 AM
Hopefully back to work again soon.

Allison's Allison
04-13-2004, 10:25 PM
What year and size motor is it? My 01' 2500HD has the 6.0 and sounds like a deisel. Was it under warranty? If not, How much did it cost to do the job?

sms
04-14-2004, 07:32 AM
Originally posted by Allison's Allison
What year and size motor is it? My 01' 2500HD has the 6.0 and sounds like a deisel. Was it under warranty? If not, How much did it cost to do the job?

It's an '02 5.3. When it was cold, about 2-3 seconds after starting it would sound like a diesel for about 10-15 seconds.
GM says it is "normal" piston slap. No ill effects, just a nusiance.
This is a pretty widespread issue in 4.8, 5.3 and 6.0's prior to 2003.
GM says it's not a problem, but will give out 100,000 mile warranties to pacify people and avoid replacing a million engines.
After being offered the warranty, I kept pushing, took my own compression and leak-down readings, etc...

The final resolution on mine was a rebuild, and the extended warranty, both no charge to me. Be a squeaky wheel, they sold you the truck knowing it would probably knock at 20,000 miles and I bet the salesman did not mention that to you.

BTW, The first time the service guy told me that it would not hurt the value, but even ENHANCE the value of my truck to have this problem because of the warranty they would provide for free, I went immediately to the showroom and told a sales guy that I wanted to trade in my truck, but please be aware that the engine knocks. Suprise! they didn't want it.

They resolve these case-by-case.

chynewalkr
04-14-2004, 05:30 PM
Do you find the seats in that truck uncomfortable? a coworker of mine had extra padding added to his seats because they work uncomfortable.