Hello today I jump started a Friend GOLF using my Jag.
Engine turned on, connected the battery poles. Everything ok so far.
Before my friend turned the engine of his car on I pushed slightly on the accelerator to give more rpm and more power to the battery, and at the same moment I head a squeak sound at my alternator. It never happened before. Neither it happened after disconnecting the battery poles.
Did It happened because of the higher load on the alternator probably ?
Any hints? Should I replace the alternator belt ?

 

Yes , there is a rotational resistance to a high alternator load

No , if you tighten up the alternator belt too much you risk limiting the service life of your alternator and water pump bearings , belt being cheap and easy to replace .

If you jump start a car , better off letting your car charge up their battery for 15 minutes first . Your car . Don't take one for a VW .