Squeaking noise whilst idling
 

Hello all,

At idle, there is a squeaking noise coming from the auxiliary drive belt area.

A Volvo dealer says that its the pulley wheel attached to the alternator; however, after removing the aux drive belt, none of the five wheels make any noise when I turn them.

I have noticed that the wheel attached to the AC compressor stops and starts, which is probably due to the AC adjusting the temp.

The aux drive belt does seem to have a lot of play in it when the engine is running, and seems to twist slightly too.

Could this noise simply be the aux drive belt being too stretched over time, preventing the tensioner from maintaining the correct tension when the engine is idling?

This does't sound right - the aux belt should be tight and true when running.

you need to check the alternator pulley, it has a one way bearing inside, to do this you need to lock the alternator and then spin the pulley, Its easy to replace and requires a 33 spline alternator tool from ebay to remove. You can also buy the pulley from ebay for 32 pounds and you get a INA pulley without the Volvo price tag as its the same pulley from Volvo.

this most definitely sounds like your alternator pulley has failed then

"aux drive belt does seem to have a lot of play in it when the engine is running, and seems to twist slightly too."

This can be the alternator freewheel - if it is mis behaving then the belt can physically waggle about in use. more so on diesels due to the severe detonation accelleration of crank pulley



Could this noise simply be the aux drive belt being too stretched over time, preventing the tensioner from maintaining the correct tension when the engine is idling?

They dont stretch.
The Tensioner is sprung and will always be set right.

Turn the a/c off and see if squeals with a/c off - to rule out a/c

Ditto alternator pulley.

Ditto ditto......
There are a few tests you can do such as flicking the pulley etc but they are inconclusive in the sense that if it is free in one direction that doesn't mean it's ok. Comparison with a new unit shows that there is 'free' and then there is 'free'.
The belt should run true and smooth at idle. A barely perceptible movement of the tensioner pulley is ok but if you can see jumping without having to peer at it it's time to replace the freewheel pulley.
They aren't a scheduled replacement item. I think they should be , at or before a timing belt change. Typically the manufacturers of these items quote a service life in the region of 80 thousand miles

Thanks guys, as you have confirmed what the Volvo dealer has said.

Looks like I will be removing my alternator in order to renew this free pulley wheel then, as Volvo wants €100 for the part and at least €200 for labour.

I just hope I can find that tool quite cheap, as it will most likely end up being a one-off use unless it can be used on all cars???

I carried mine to the local auto electrical repair shop. Starters,alternators etc. The INA part was there at 80 Euro. I had brought my own new part from Volvo ( a bit more than the 80) and he fitted it for free in five minutes chatting over the counter.
They're not all like that obvoiusly, point being I didn't get yet another special tool and he gave the alternator the once over when I was there.

The tools are easy enough to use and the 33 spline is a pretty common industry standard.
I'd chewed my old tool though so when I bought my genuine Volvo pulley, I took in my alternator to the parts counter and they replaced it within the price which was about £75 so the same cost as a good oem pulley+the tool.