Volvo: 1997 Volvo 850 Heater, center vents, air mixture

Question
Hello Jimmy!

We have a 97 Volvo 850 sedan with 130K. The heater does not provide heat correctly. On a cold evening (35F)wih the two controls rotated to full heat... no heat available while driving around after 5-10 min's warm-up, BUT,...I asked my girlfriend on the phone to turn the controls to cold and back to hot. She told me that when she turned the controls to cold the eng temp incresed somewhat. When returned to hot settings the engine heat again decreased (that sounds normal to me, cold air from the plumbing circulating cooled the eng slightly.) After she arrived at her Dad's home 15-20 min's later, dad went out to the car, started it and the temp was normal and heating was very good. It seems that when driving the car there is a very small amount of heat provided, when at a standstill there seems to be a normal amount of heat. (Almost sounds like there is a massive outside air mixture door, On the next drive we will try the recirc control) Hmm,  Got any ideas?
Thank you, Grey

Answer
Hello Grey! There are a few things you cna check. First, make sure the the cooling system is filled with the proper amount of anti-freeze. There could be a fault with the thermostat. I would replace it, if you haven't already. Also, make sure the "air mix" knob is in the correct position. If it is set incorrectly, that will cause cold air to flow from the center vents. I'll be here if you need more help.

Jimmy