Hi, I have 1998 F150 wtih 4.6 litre,,, I feel like more air sound ( I don't know its a intake or radiator fan or whatever), when every time start move from a stop. It happens in every signals, traffic and even just start the truck and move, same thing happening. It become normal once it picks speed....not feel like more air sound. Please need some understanding.

 

Thats the fan spinning faster. it can get really loud if its hot out.

 

Check and see if you can spin your fan by had with the engine off. If not the clutch is locked up and you need a new one. If it spins than the clutch is fine and engaging as your engine heats up while stopped.

 

Thanks for the feed back. I did check, while the engine is off. Fan can be rotate...