awdinut

2006 A6 ...After driving about a half hour A/C blows hot air, even after the climate control is switched off. After driving another half hour or so , I can switch the A/c back on and get cold air for another half hour; and so it goes. I had the A/C examined and nothing was found to be a miss. ???

LarryJa

I had that problem & had to disassemble the heat control solenoids, to clean the actuation plungers, about a year ago. There's a good thread on hot air blowing out of dash vents in this forum. Search for it, & clean your control solenoids up at the cowl area.

awdinut

I searched extensively before I started the thread and never saw any applicable threads, sorry. But, since you had the same AC problem, could you supply more detail as to what you did to "clean the solenoids" and cure the problem ? As I understand the HVAC system, the solenoids control the passage of hot water to the heater cores. How did they affect the A/C temp; and what was the dynamic with solenoids that allowed cold air for the 20 min intervals ?

hrc4u

https://www.audiworld.com/forums/a6-.../#post24288059

Cheers /H