I have a 2007 XC70 Cross Country and just had my thermostst replaced @ 70K miles. At idle the temp guage won't come up to the mid temp range. However, once I start driving, the temp quickly comes up to proper range. Is this normal? My problem is when I'm warming the car up in the driveway and put the setting on defrost to de-ice the windshield, it doesn't get hot enough to do the job properly. I can only get proper temp once I start driving. Is there a safety on the thermostat when the car is in park and idleing?

 

This sounds like an air pocket in the coolant system. If the stat was NOT replaced by a volvo mechanic, I would guess they would not know the procedure to burp the system!
I would remedy this or risk overheating and not knowing till its too late!

 

I have the same issue. Did you find a definitive answer? I am trying to do a little diagnostic work before I start buying parts and ripping things apart.