What is the popcorn noise under the hood?
Something the popping doesn't occur until 1 or 2 hr after I pull into the driveway.

Thanks,
Tin

 

If no smoke or odd smells are present, it is probably just hot metal such as exhaust, truck body under the hood, oil pan, internal engine components etc., cooling down after you shut the engine off. They expand gradually as the engine heats up but when you cut the engine off they cool quicker because to a 200F engine, an outside temp of 85F is as cool as ice since it is 125F cooler. Normal for all cars. Now if your car blows up because the popcorn noise is actually that live 1000 Volt power transmission line you have been dragging under the truck since you missed the turn, don't blame me.