Have just bought a 2006 Fiat Punto 1.9 multijet sports. It has a loud rattle and I have been told it's the aircon compressor. I was also told that I could bypass this unit and put a smaller belt on as the compressor unit from Fiat would cost £600+ fitted. The mechanic said he would not fit the smaller belt as it was a bodge. I am not that flushed with the readies, so what belt should I fit and is it an easy job? I won't nead the aircon until next year and I might get used to not having it. PS new to site looked through the newbie instructions and am now even more confused on how to use site.

When the air con is turned off it shouldnt rattle even though it will be spinning, there is a clutch in the air con unit that engages the compressor when you turn air con on so it shouldnt be making noise unless the pulley for the air con isnt running true - this you need to sort because it will mess with the other pulleys on the aux belt and the belt it self. OR the clutch for the compressor has stopped working if the noise is all the time without air con on.

£600 to change the aux belt is ridiculous just so you know.

Welcome & You can't go wrong fetching here for knowledge Good Luck.