Dear Motor Medics,
My 2004 Chevy Tahoe has had a knock when cold since it was a couple years old and the dealership where I bought it always told me it was normal and it wouldn’t hurt anything and I did hear it in others so I wasn’t too alarmed but now its knocking all the time and slightly worse. I’ve got 250k miles on it and I’m hoping to get at least another 50k out of her.
Terry in Valentine Nebraska
We’ve been listening to the dreaded Chevy 5.3 knock for years and sometimes we wonder if we have become numb to it. It’s so common that we don’t usually think twice about it. The engines have some piston slap noise that is worse when cold but once parts warm and expand they take up the slack and stop knocking. The dealer was right in saying that if this is the sound you have that it won’t cause harm but now you’re reaching the engines mature stage and those noises may have nothing to do with the inherent noise of the 5.3. At 250k it could be a normal loose engine or it could be getting ready to fail. Either way it’s been a long life for it and that’s good miles for a 5.3 even though some go longer. Have your local shop take a look and hopefully they will surprise you and say it’s still good to go for awhile.
Take care, the Motor Medics