Hopefully some one can shed some light on this issue for me. A while back when my head gasket was starting to go, I noticed a rushing sound in the heater core area. Sure enough w/ your help - The headgasket was shot.
Just last night on the ride home - I heard the sound again coming through the heater core, Not only when I first started it but also when driving around randomly. Fluids full, No exhaust smell in the radiator fluid, and I don't smell like a burning candy shop. I am 100% Baffled on this whole ordeal.
My mechanic said sometimes these trucks do that if you have your heater on (say its a cold night, like it's quickly becoming) and when you start it the next morning it will do that.

I dunno, No one elses vehicles do this. Im gearing up to do a compression test on the engine, and ive checked all the fluids and smelled everything. What should I do next? Check spark plugs for build up?

Also, this truck has the OEM thermostat and it always temp spikes wether its the 1st time or 14th time ive started/driven the truck. Any advice at all is appreciated -Thx