2009 XC70 low cabin heat

[Kach]

Hello! I just picked up a 2009 XC70 T6 (haven’t had a Volvo since my 2002 XC 10 or so years ago). I’m loving this car - a slightly updated version of the same thing.

I somehow didn’t notice on the first couple of days I owned it, but it’s definitely not putting out much cabin heat and barely keeps the windows defrosted. I’m going to work on diagnosing today. Any tips on figuring this out?

I’m leaning toward needing a thermostat so far. I drove the car skiing yesterday with temps in the 20’s. There was minimal heat (Luke warm) on the open highway drive. After working the car harder up the mountain pass and then parking, the heat was much better and car warmed up quickly. This makes me think the blend door and core are probably good. Most likely seems like the T-stat is stuck open and open road driving doesn’t let the car fully warm up.

I couldn’t monitor the engine temp due to a bulb out warning (never figured out how to clear it while driving).

Found lots of old posts on the P2 cars but not much for this generation…

[Kach]

Update - looks like both heater core hoses through the firewall are about 92* F, engine not getting above 135* after driving around. Still suspecting T stat stuck open.