80 300D(non turbo) Overheating?

[psdsteve]

MY brother is is Arkansas or I would drive over and check it out. However he is having a problem that sounded wierd to me and I'm looking for enlightenment.

He said that it started running warmer than normal and the alternator light is flickering on and off. When he looked under the hood he said that the alternator belt seemd to be moving slower than the pullies were rotating. Is this possible without the belt getting burned up? I didn't know if there is a mechanism that could allow this to happen in a Merceds. Any input would be appreciated.

Thanks,

Stephen