'06 R53m - 122k miles
I've had a weird issue with my A/C that was noticeable before but was not nearly as severe. This summer it's gotten so bad that I've taken to driving my wife's car to work.

The first problem is that my A/C takes a while to "cool off". I would say after about 10-15 min of driving it is working well enough. The second and significantly more frustrating problem is that the driver side (left) AC vents are both significantly warmer than the passenger vents. I was so surprised by this that I actually got a digital thermometer to measure the difference.
After approx 15 min of driving I and the AC on LO and re-circ on I measured the temps in the four vents. The passenger vents were 65 and 66F. The driver's side vents were 76 F.

What exactly could be going on that the other two vents are 10F warmer?? Has anyone else had an issue like this? The heater works fine and there doesn't seem to be a difference between vents there.

 

sounds like one of the 'flaps' that change the air routing is stuck

and you probably should get the gas pressure checked - any a/c place can do this, and fill it if needed. for an 06 to need the refridg' gas topped off is no big deal IF no leak is found on top of that.

 

Thanks for the input. I will say the HVAC system is the one part I've never messed with on any car.

Is there something that prevents coolant from moving into the heater core until the heat is turned on?? I notice the center unit behind the HVAC controls is quite hot to touch whenever the engine is warmed up. If I set my leg on it I feel like I'm going to get burned.

As for the "flaps", according to the Bentley service manual the HVAC for the IHKA panel (Cooper S) is controlled electrically through distribution servo motors. One for the temperature control, one for recirculation control and one for air distribution control.
The air distribution control seems to be the one nearest the driver leg. I'm guessing that might be the one that is stuck?
"Remove IHKA Control panel"
"-Detach electrical harness connector"
"-Remove mounting screws and pull servo away from flap mechanism"

I guess either the servo is bad and only partially working or the flap is just getting stuck.

 

Yes, There is a heater valve to control coolant flow to the heater core. They can fail open so you get heat when you don't want it. But usually you would get good cold air when the engine is still cold, and then it would start blowing hot as the engine heated up.

 

That's interesting. What else could be causing that panel to heat up but the heater core??
Its this panel that I'm pointing at next to the gas pedal (sorry its washed out a little)

 

Yep, right behind that is your heater core. But, your symptoms don't exactly fit but perhaps you have a leaky heater valve -and- are low on refrigerant...

I would try and check those air distribution flaps, also, before doing anything drastic

 

ever take a look at where the exhaust runs?

I think if you search back to when GEN1 was new you'll find many threads about "cooked feet"
(never mind, I tried. I remember the topic but can't hit on a way/ keyword to pull 'em up (and some EARLY stuff disappeared from this site as I recall))

an old post mentioned finding an air bubble blocking the heater core flow ... you could try bleeding .....

hmmmm sounds like ancient medical advice!