I have a 2007 XC90 3.2 AWD. The Volvo dealership service tells me that the alternator is always running, which is not supposed to happen, so they need to replace the alternator clutch. Dealer tells me it will damage the alternator over time. Quote is $1,250.

I thought the alternator was always engaged, even when idling. Does the alternator engage / disengage on the 2007 XC90's? The dealer replaced the alternator clutch pulley last year but I haven't been able to find the difference between the alternator clutch and the alternator clutch pulley.

 

As far as I know, the alternator is always alternating when the engine is running. The clutch is there in case the alternator seizes so that the timing chain components do not get damaged - yes the timing chain drives the alternator and the water pump. I can check with my techs on Monday to firm this up.

Tim

 

Even if it's supposed to declutch, every car I own has an alternator that runs all the time, and several of these alternators are 40 years old and work fine.

 

This link may help you with your query.

http://www.decouplerpulley.com/files...a%20pulley.pdf

If you had the alternator clutch pulley recently replaced it should not need renewing so soon. The cost sounds excessive too.