air dryer filter?

On left frame rail, under cab, inside frame.

 

I doubt that's your problem but it wouldn't hurt to change it. The "sneezer" on the bottom of the drier probably has a bit of ice in it. Usually it will work it's way out on it's own.

 

try warming it up some (the sneezer) with a pencil torch or other flame. I carry a heat gun with me for my electrical heat shrink tubes, thawing out brakes, ect... and I'll either finr a Idleaire or a plug outside a shop/C store and plug in my extension cord.

 

if the air govenor is freezing up and making that horrible sound put some air guard in system, please dont use rubbing alcohol it has water in it

 

you can use pure alcohol available in drag store (sold in small bottles for medical use). One small bottle is enought to put in wet tank.

after that change filter