fan belt keeps on jumping out when egine is running
The most likely things that will make your belt jump off would be. 1. A bad bearing. 2. A belt that is worn. 3. A belt that is too loose. 4. Any combination of these. While the engine is running watch the belt and see if the pulley has a wobble, if the belt looks too loose or if you hear a grinding or hissing noise coming from the pulleys associated with that belt.