When the A/C in my Coupe started blowing hot air out the Driver-Side but cold air out the Passenger-Side, I performed the attached temporary flush to see if the Duo Valve was simply clogged up with residue from the Coolant. Turns out that fixed the hot air flowing out the Driver-Side and the system continues to perform to this day (been close to 2 years since I did the flush). With a try!