Early A/C Control Question
Thread Starter
CF JASOC Member
Joined: Feb 2006
Posts: 8,040
Likes: 34
From: Downtown Annapolis, MD. The Future is where we all have to live. Let's not screw it up.
St. Jude Donor '08-'09-'10-'11
Early A/C Control Question
'71 A/C car.
Question...
Should there ever be a time when you hear a vacuum noise (hissing) heard from the control head under the console when moving the wheel from one position to the other?
Before I take the center console apart to have a look around, I figured I would ask you guys if this is normal first.
Found my "hot air from the vents in cold position" problem. Vacuum line to hot water valve was leaking at the valve from not being pushed on all the way. Thank God it's right behind the fender vent and easy to get to.
Question...
Should there ever be a time when you hear a vacuum noise (hissing) heard from the control head under the console when moving the wheel from one position to the other?
Before I take the center console apart to have a look around, I figured I would ask you guys if this is normal first.
Found my "hot air from the vents in cold position" problem. Vacuum line to hot water valve was leaking at the valve from not being pushed on all the way. Thank God it's right behind the fender vent and easy to get to.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
You will hear hissing as the control is moved from one position to another. After the move and after the actuator diaphragm(s) have completed their tasks, there should be no more hissing sound. Do the various positions on the control work as intended?
Thread Starter
CF JASOC Member
Joined: Feb 2006
Posts: 8,040
Likes: 34
From: Downtown Annapolis, MD. The Future is where we all have to live. Let's not screw it up.
St. Jude Donor '08-'09-'10-'11
Yes, brief hissing as the control is moved between functions. Quiet before and after. That's a relief.
The positions seem to be operating the various functions properly, but the only position that seems to open the vacuum controlled door on the passenger kick panel is MAX A/C.
I figured it would be closed for MAX A/C, and open for others.
The positions seem to be operating the various functions properly, but the only position that seems to open the vacuum controlled door on the passenger kick panel is MAX A/C.
I figured it would be closed for MAX A/C, and open for others.
Racer
Joined: Aug 2001
Posts: 388
Likes: 1
From: Bridgeport CT
Gentlemen:
I disagree. When and where it hisses tells you there is a problem. New cars don’t hiss, and that includes new old C3 Corvettes that I have had. If while changing climate modes you can hear a hissing sound, that is indicative of a worn leaking rotary valve. When new, there is no perceptible sound. They are zinc die cast; strong but not very hard surfaced. This material (called pot metal) like a carb is susceptible to wear from movement. With aging and use they begin to leak.
Repair yours and seal with the same high vacuum grease as used on power brakes. (This lube is not the same as wheel bearing grease.) Or purchase another one new. Used one’s will generally be leaker’s also.
Geoffrey Coenen
I disagree. When and where it hisses tells you there is a problem. New cars don’t hiss, and that includes new old C3 Corvettes that I have had. If while changing climate modes you can hear a hissing sound, that is indicative of a worn leaking rotary valve. When new, there is no perceptible sound. They are zinc die cast; strong but not very hard surfaced. This material (called pot metal) like a carb is susceptible to wear from movement. With aging and use they begin to leak.
Repair yours and seal with the same high vacuum grease as used on power brakes. (This lube is not the same as wheel bearing grease.) Or purchase another one new. Used one’s will generally be leaker’s also.
Geoffrey Coenen
