of being in the garage(rather snowy/nasty here) to warm it up. All seemed fine as I backed out of the garage, let her sit a while then pulled it back into the garage. Figured I pop the hood and check things out visually and I hear this rather loud chatter. Sort of like cards in the spokes of a bike wheel AND after some poking around to see if some tape was hitting something, NOTHING VISIBLE, I seemed to narrow it down to the drivers side below the intake manifold.

after shutting her down and then starting her up again I could not herar the noise again. COULD THIS BE PISTON SLAP after sitting in my garage so long? Should I be worried about something else..... 52,000 miles

 

Sounds like it could be. Mine only does it sometimes on cold starts and then goes away after it is warmed up.

I'v heard people on the board say that when storing a car it is better to not turn it on at all then turn it on and leave it park.

 

despite what some people say this symptom is normal and harmless.reputable sources outside GM have confirmed this.an article i read even stated that people have become so paticuliar they expect big HP motors not to make any noises.


people have had their motors torn down and pistons replaced but they wasted their time over a little noise.

 

Good point, I should have mentioned it's not usually anything to worry about. Especially if it goes away after the car warms up. The reason it is common when the engine has not warmed up is because of the different materials used in the engine expand at different rates, the materials expanding at a different rate causes the piston to have a little room to move side to side.