99+ 5.3L piston slap

[dtlilly]

My dad has a 2002 GMC 1/2 ton 4X4 with the 5.3L V-8 and 30,000 miles. When cold at initial start up, the engine sounds like cotton gin rattling. He went to the dealer to have it looked at, and the service manager showed him a letter from GM talking about the engine noise being piston slap. GM only issued a service memo, not a recommended service advice. Screw GM... I'll never buy a new truck from them.

[Sublvr72]

its normal, my 6.0L does not do it (yet) knock on wood.

[Josh]

It's normal, and really won't hurt a thing... My tahoe does it, about half of the trucks I work on do it, they use really short piston skirts to reduce weight and friction (hence how a full size truck has 295hp and gets 19mpg hwy) It's VERY annoying on cold start up, but I've seen 5.3s with 200k+ miles that did the cold knock since 25-30k and they still run like a champ... Mine didnt start it till about 60k miles...

[dtlilly]

Thank you for the reassurance, I'll be talking to my dad later this week, and I'll make sure to tell him not to worry too much.

[Jeremy_5]

here is a link to a thread about the same piston slap problem http://207.44.196.117/vboard/showthread.php3?t=143740

Also I read a few months back that GM was being taken to court over this problem.

[T_Raven]

my 00 does it. wasn't sure if it was piston slap or if i had a lifter going bad that took a while to pump up when cold. but if it's that common i won't worry about it.

[Joe67]

IMO that whole thing was blown way out of proportion.

I've had it on my 2000 5.3l since day one. I have over 145K miles now with zero problems.

[67ChevyRedneck]

hmmmm, brought this one back from the dead. My truck is a '00 with the 5.3. Has piston slap on "cold starts" on days where its about 50 or below outside. Does it for 10-20 seconds. Truck has 80K and runs great.

[Werewolf]

Might as well resurrect it once more.

My '01 has it at 107k miles. I used to have a '02 I had bought new that ended up starting it at 5000 miles. It may not hurt anything, but it's really depressing that a brand new truck makes that much racket. A lot of people, at some point, found it highly annoying, and were threatening to sue GM over it. There were even rumors of "egg shaped cylinders" being formed over time, and excessive oil usage due to the piston slap. I've never spoken to anybody that had that problem, but I hear about the piston slap thing all the time.

The '03 (or maybe '04) and up engines have redesigned piston skirts that will prevent that from happening. Actually, the '99 to '02 trucks don't really have piston skirts at all, per se. From what I heard, once, GM used computers to design the engine, making it as efficient as possible. The computers said that they could build these engines with little-to-no skirts, and that it wouldn't be a problem. What nobody figured out is that computers deal with ideal situations, and that friction, over time, would end up causing the engines to wear in and make some noise.

My '01 is occasionally doing it now when it's warmed up, as well. I'm not too worried about it yet, but I may just get a 6.0 for the truck soon, anyway. It's been acting up since I changed the 187 'stat out for a 160. Apparently the engine doesn't like the colder temperatures.

[67ChevyRedneck]

Some late year '02 supposedly have the "fixed engines" and all '03's should have them.

[Longhorn Al]

I have an '02 5.3L and haven't heard the slap yet. I've got 71k on it.

[Joe67]

Originally Posted by Longhorn Al

I have an '02 5.3L and haven't heard the slap yet. I've got 71k on it.

By the 2002 model year, GM corrected the issue

[Longhorn Al]

Good news.