i noticed belt noise came on when i turn on A/C, and disappeared after i turn off A/C, is it the alternator belt?

 

Sounds like you need a new belt tensioner. I'd replace the belt with it and also check the other pulleys for bearing wear.

 

thanks 98roverguy

do you mean alternator belt tensioner or any other belt tensioner?

 

First of all, what year is your truck?
Have you looked to see what your engine has for a belt?
Mike

 

2003 disco II S

78000km

 

You stated your mileage in km so I'm assuming your in Europe/England and have a diesel Tdi?

 

So, all D2's have 1 serpentine belt that deives everything. Not knowing how long it has been since you changed them out, I would suggest a belt, a belt tensioner and a idler pulley.
Also, I would suggest you get in under the hood and become more familiar with your truck, if you ever really have a problem or break down you will wish you knew more about what you drive.
Good luck,
Mike