[aurelyannn]

Hello,

i have a small noise when the engine starts on the transmision belt. The belt seems to look fine. Need to change?
Tks!

[Billfitz]

If you mean the serpentine belt you should treat it with this or something similar as part of your regular maintenance routine:
https://www.amazon.com/CRC-05350-Bel...00M8PZB4&psc=1

[auburnf30x]

Be careful using belt conditioner, too much can actually make the problem worse.

First thing I'd do is pull your belt and give it a good cleaning. Spilled grease or oil can make the belt slip. While the belt is off, rotate each pulley on the engine to make sure they all spin freely and don't have too much wobble. Of course, the crank pulley won't turn. Put your belt back on and check the tension on your tensioner. I haven't looked at the F30's tensioner yet, but most of them have a mark on it to verify the tensioner is keeping a specific amount of pressure on the belt.

Assuming all pulleys spin freely and smoothy, and the tension is within range, start your engine and see what it does. If it is quiet, your belt just needed a cleaning. If not, replace your belt. Sometimes cleaning the belt will also make the noise disappear temporarily. But again, if it comes back, new belt.

[aurelyannn]

Thank you !

[Vincenz099]

The belt should be changed regulary regardless, I assume your car is like 10 years old by now, which means it's long overdo.