S80 Intermittent heat related to strange noise

MHaas · Post by **MHaas** » 08 Dec 2008, 11:58

When I bought my 2006 S80 (my first Volvo), it had 68K miles. It was summer and I noticed a whirring sound coming from behind the dash. It would "whirr" for a second, then stop, then start again and would repeat this until I turned up the radio to drown it out. This winter I have noticed the heater blows cold air for one second, then hot, then cold, etc. It does this the ENTIRE time the heat is on, but the cabin eventually gets warm. The change in air temp. coincides perfectly with this noise. Apparently some valve is opening and closing continuously and I'm thinking it is some sort of relay, but as this is my first Volvo, I don't even know where to start. Any ideas?? (I'm trying to love this Volvo but these things are quirky!)

Post by **MadeInJapan** » 08 Dec 2008, 15:33

Probably the motor that changes the dampener. It is letting in air from the outside then closing up to allow warm air from the heater but it won't stay for some reason and goes back to the outside air. On older cars I know a bit about this but for newer ones, I wouldn't have a clue. It might be as simple as a software reset. I'd take it to the dealer for this issue.