pwhite52

Recently the A/C unit ('96 993 C2 w/52,000 mi) has developed a wheezing noise under acceleration. When under constant throttle pressure I get cold air but if I accelerate at all, the vents stop emitting any air, or emit low pressure warm air. Then once I ease up, normal cold air again. Is this a CCU, servo, mixing flap, compressor or what problem? Thanks for any input you may have.

pp000830

http://www.bergvillfx.com/porschehvac1.html

lopro

I have pulled a complete working a/c system off a clean 993 just let me know if you can use any parts

techman1

most likely a vacuum leak. spent many hours tracking mine down. it was the vacuum for the reverse changeover valve for the air intake when you go into reverse.

ToreB

I agree on the note of a vacuum leak. This makes the resirc flap to become saggy under acceleration. I also had the leak in the reverse air intake changeover valve. This is described in the above mentioned HVAC DIY.
Cheers,
Tore

therossinator

Not many things on the HVAC system are dependent on the the speed of the engine. Check all vacuum connections, esp. the one behind the CCU.

chsu74

My weird case:

My AC does not blow air in fan settings 1 and 2. It blows well in 3 and 4. Last year, it was fine at 2 while 1 setting was not blowing air.

Is my rear fan going out which is shutting down air flow?

Evap replaced two years ago.

Thanks