I've got a '07 Silverado 5.3L (flex fuel engine) with just under 3K miles. Periodically at a cold start up(but sometimes when the engine is warm) I get a rattle from one or more lifters. The noiseusually only lasts up to 10 seconds, however it will occasionally go on for close to a minute before all quiets down.The dealerwas able to replicate the problem, but not long enough to identify what was going on. Dealer changed the oil at just under 2K miles, but that doesn't seem to have made any real difference. The noise happens frequently (but not all the time) regardless of outside temperature or if I've recently driven the truck. I've got a friend who has the same engine in a '07 Avalanche and he's experiencing the same thing. Anybody else?

 

I've got 4,000 on my '07 5.3 and haven't noticed the same noise. I don't have the flex fuel.

Does your friends Avalanche have the flex fuel too?

 

I just bought a 01 and have the same noise, I talked to a friend who has a 03 he bought new, he worked in a chevy dealership and he said his does the lifter knocking too in the morning like mine. He said it a common problem he hear alot about with the 5.3L.

I think the 5.3L comes with roller lifters so Ive been wondering if there is a the possible connection between the noise comeing from the area of the #1 cylinder and roller rockers?

I changed my oil last weekend and the noise is not as loud in the mornings.

 

I think my friend's Avalanche is also flex fuel and I'm pretty surethat the 5.3L does have roller lifters. The noise definitely seems to be coming from the #1 cylnder area. I guess as long as it isintermittentI shouldn't worry about it, but it doesn't seem right. I never noticed this happening with my '95 Silverado, even when it got close to 80K miles.

 

What a coincidnce, tonight my wife just ask me to look at her truck because she thinks the lifters are knocking on her '06. I didnt know she knew what a lifter was.

 

Speaking for the 4.3L crowd here, we have that problem too.

 

After spending a bit of time surfing the net on this matter, it seems that this engine issue has been going on for quite a while. It also seems that GM is holding this out to be a "normal" condition and is not doing anything about it until (if even then) something breaks. I guess they figure most won't notice the noise or keep their respective vehicles long enough to experience some type of engine failure.