Motor Slap

[Rjbeck77]

Just wanted to ask if anyone else experiences a slapping sound when they first start their truck. I've started to notice it more and more lately.

I have an 09 Sierra, 5.3 with about 60,k miles.

Thank you!

 

[2001gmc]

For whatever its worth I have a 2001 GMC Z71 that I bought brand new in 2000. The day it got 20,000 miles on it I was working telecommunications on the road. I started up the truck and immediately shut it off. It knocked so bad I thought something was really bad wrong. I took it in to the dealer and they said it was normal. I been driving it ever since. I now have over 200,000 miles on it and haven't had 1 single issue with the truck. If its cold outside it sounds like it has a rod knocking bad but it goes away in like 30 seconds after its started up.

 

[Rjbeck77]

Thank you for your reply. I may have a mechanic check it out. Maybe some peace of mind.

 

[poncho62]

Its called piston slap...the pistons get a bit worn and flop back and forth in the cylinder until it warms up and expands....Chevys seem to be known for this

 

[H/H Specialist]

You will get used to it.. If not sell the truck

 

[Bill325]

My 2000 GMC Sierra with the 5.3 liter engine also has a rap for the first 30 seconds or so . After that, most of the noise goes away . Don't feel too badly about it, as many high performance engines with forged pistons also have a piston slap until they are warm.