my 09 aveo rattles for a few seconds after sitting overnight. If I start it after about 5 hours max, its quiet. Florida weather, so I think its time sitting rather then temp. Its sounds to me like the oil pump is loosing its prime? My info.. I'm a mechanic for 42 years and just about to retire. But I'm hoping some gurus out there can give me their input. Here is the car history, bought this from A customer due to timing belt gone and valve going through the piston. UGH. so 4 new auto7 pistons,rings, reman head from Texas, timing kit,head bolts,seals,gaskets,etc. car runs great, but I'm concerned about the noise. swung back the a/c compressor and checked the oil check valve. checked ok. Scan data,running shows int and exh phasers in spec. So, to wrap a long post, anybody out there have suggestions? (other than if you've been in the field for that long and can't figure it out,yer in the wrong business LOL) thanks