Recently replaced all the belts on my 1974 f-250 and now I get a schreech when I start it up, it goes away pretty quickly.
What could be the culprit, too tight or too lose fan belt(s)

 

Most of the time it is because the belt is not tight enough. We always want to make sure the water pump and alternator don't have bad bearings.

If the water pump pulley and alt pulley rotate easily, with no roughness or noise, then when we tighten a new belt it usually eliminates the squeal on start up.

 

I just replaced the water pump so it should be fine, I'll check the alternator to see if it's spinning free and replace it if it isn't.

Thank you for your input