Hello I am new to the forum I have a 2008 Silverado with the Duramax. The truck is completely stock except I just recently purchased a tuner. I am happy with the millage and power gain so far. The only thing I am not thrilled about is until the truck gets to about 160 degrees it is noisy ( clatters like it is an older diesel ). I talked to the manufacturer and they said this happens on about 10 percent of the trucks they tune. Is this a problem I should be worried about or is it fairly normal. I do not want to list the programmer. Thanks
Andy

 

This is normally from the programer raising the timing but not adjusting for cold temps properly. Ie: a pour tune.

Rattling or knocking is hard on the head gaskets, pistons and rods. I would not run it like this. Eather find a better tuner or better yet get efi live.

 

Thanks they have already offered a full refund.

 

What's kind of tuner?

DieselDawg