engine fumes

I sometimes get what looks like engine fumes coming into the cab. I know when its going to happen because my windscreen starts to mist up. The colour is white fumes.:doh:

ARE you sure its not steam mate from the heater or the pipes cos steam will condense on a cold windscreen and give the symtoms you describe,if its engine fumes you will see something in the engine bay,oil all over the bay ,loss of engine oil,oil dripping of bottom of engine,if the fumes are that bad there must be some evidence somewere else,keep investigating mate its there somewere best o luck ....dave

The drain at the bottom of your heater air intake (on the wing) is blocked.

Thanks I will check it out and let you know how I get on.