I have a 96 grand am GT, and the thing sounds like it's knocking when I start it up. Give it about, 3 minutes of running time, and that sound dissapears. I usually run synthetic in my car, but the last gasket I got changed, the dude put regular in. :\
Either way, I've noticed this sound for a while now, seems to only do it in the cold tempuratures. My friends brand new malibu does the same thing, only during cold tempuratures.... is this something I should worry about? Is it causing damage if I drive it during those 3 minutes of 'warm up time' ?
Thanks.