skemper,
I had a similar problem last week with my 84. The hose mercedesmatt refered to was loose. I tightened it up and the problem went away. Find the alternator and go back about a foot and you should see it.

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K