Did a search and couldn't find any info on this topic. If my car sits for a couple of days without use there are loud clicking and thumping noises from the engine for about 3-4 seconds after a cold startup. It sounds familiar to lifter noise and rod knock at the same time. Engine has no mods and I've been using Mobil 1 5/30 with factory filter changed every 3K. Car has 24K on it now. I know the oil goes to the pan so there's no lube in the motor, but shouldn't there be enough residual lube on the mechanicals to keep this from happening? I hear this noise 1 out 4 times when the above situation occurs. Have I got bad internals, or is this a normal occurance? Sure does seem like this would have the potential to severly shorten the life of the motor.