Newbie to the board-Need help with piston slap

[draftsman]

Hey, how are ya'll doin?

About a month and a half ago i upgraded from a '90 GMC P/U to a '99 with the 5.3L engine. I think i got the good ole 'piston slap' with it.

It hasn't been bad, only a quick few seconds on cold starts until this morning. Rainy shitty morning today, started it up and the knock was much louder than normal. Let the truck run 4-5 mins hopin it would go away but didn't. The noise stayed at the same volume and same pattern. Shut the truck off and brought the ole '90 to work.

Two weeks after originally buyin the truck it did the same thing but the knock quieted down after 3-5 mins and i drove the truck to the dealership and they told me they put an oil pump in it. $400 fix.

Sounds like the same thing other people on this board are having problems with, piston slap, knocking, sounds like a lifter...that sort of thing.

What i'm worried about is that the sound never went away after 5 mins. Think this is bad enough i should get it checked out or is it just a bad day for this friggin piston slap? BTW i have great oil pressure too. The truck has 98,000 kms on it.

I just found this forum today so i'm kinda new to it, quickly looked over some previous posts and found that theres a ton of knowledegable people on here to help with my questions

Thanks, in advance, for the help, it is greatly appreciated,

Andy

[nick0750]

http://www.pistonslap.com/

[macktoschool]

That's funny you say that. I looked up a TSB from GM, and they say that the "slap" is just some carbon that gets on the pistons around 19000 -26000 miles, and that it will not affect engine life. I have a 2000 GMC 5.3 with the same deal.

[macktoschool]

Wow, I just went to the pistonslap website. I am so Pi**** off. I sure hope there is a recall coming. I was told that mine was normal, and don't have any paperwork to help me out. Pretty shifty work by the General.

[draftsman]

Just an update here. I apparently do have the piston slap however i had something else along with it. I had coolant in my oil.

The piston slap was only part of my noise on start up...i had some clacking in the valve train too.

Took the truck to the mechanic a while back and he tore it down. Found lots of crap under the valve covers and below the intake. Pasty, gummy stuff left from where the coolant and oil had mixed.

We never did find a clear problem inside the engine. Did a pressure check on the heads as well as checked em for flat. The only thing that was found was the head bolts. Apparently besides the regular head bolts there is another row of smaller bolts along the inside edge of the head. None of these on the passenger side head were tight. Mechanic determined the coolant must have been seeping by at that point.

Every thing was reassembled and the truck is workin fine now. I've yet to hear of anyone else having a similar problem, but i'm sure i'm not the only one.

Don't know if this helps anyone or not but just thought i'd let ya know what happened. I think it was caught in time before much damage was done to the bottom end of the engine. Engine sounds fine and runs good.

Thanks for the help btw.