View Full Version : no air flow from a/c
CHEVY TECH Jul 3rd, 02, 04:30 AM OK, I'M NEW TO HERE SO BEAR WITH ME. I WORK AT A CHEVY DEALERSHIP AND A CUST BROUGHT IN A BEAUTIFUL 69 SS 396 4SPD CAR THAT HE JUST BOUGHT WITH A LIST OF CONCERNS. THE LAST ONE THAT I HAVE TO FIX IS VERY LITTLE AIR FLOW FROM A/C VENTS. THE A/C DOES BLOW COLD AND THE FAN OPERATES ON ALL SPEEDS BUT VERY LITTLE AIR FLOW. I'VE NOTICED THAT THE DOOR ON PASS KICK PANEL HAS NO ACTUATOR, (THERE WAS A SCREW HOLDING THE DOOR SHUT) THE FRESH AIR DOOR UNDER THE COWL HAS NO VACUUM LINE, THERE IS'NT EVEN A VACUUM LINE FROM THE ENGINE TO THE INSIDE OF THE CAR, AND THERE IS A OPENING ON TOP OF THE LOWER HEATER BOX THAT IS DUCT TAPED SHUT AND THE HOLE IN THE UPPER BOX UNDER DASH IS TAPED SHUT ALSO. WHAT SHOULD BE HERE???? DOES ANYONE HAVE ANY EXPLODED PICTURES OR DIAGRAMS FOR THE UNDER DASH DUCT WORK AND HEATER-A/C CONTROLS?? I NEED TO GET IT FIXED, ANY HELP WOULD BE GREAT.
Everett#2390 Jul 3rd, 02, 07:20 AM Welcome to the Club!
There is alot of knowledge here, but, I cannot help you other than suggesting for you to hit your dealer's library and use an older book, GM used pretty much all the same color hoses and wiring through out the Chevy line.
So if you find for a full-size, (Impala) or another intermediate, (Nova), at least this would help some.
There should be a line from the manifold thru the firewall to the heater controls panel to control/route vacuum for doors and water valve.
It would be interesting to share A/C temp out of duct with a POA system in recirculate, fan at med speed and what evap pressure reading would be, along with sight glass viewing. The reason I ask, I'm working on a '71 Chevy Cheyenne and the coldest it can get is 56*. Tubes are sweating, & evap pressure is at ~30-35 psi@ 1500 rpm. Should be colder...
Hopefully others here will chime in and help...
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Everett 68/350/PG/11.90/115mph
CHEVY TECH Jul 3rd, 02, 07:31 AM THANK TOU FOR YOUR REPLY EVERETT. THIS CAR DOES NOT HAVE A POA VALVE ANYMORE, IT HAS SOME SORT OF REPLACEMENT TUBE THAT IS JUST STRAIGHT THROUGH WITH A LOW PRESSURE CYCLING
SWITCH NOW, KINDA SLICK REALLY, NO MORE TROUBLESOME POA. ON YOUR 71 PU, HAVE YOU CHECKED YOUR HEATER CONTROL VALVE, I HAVE A 69 C10 W/91 TBI 350 AND A/C. MY VENT TEMP WAS ONLY IN THE 50'S. MAKE SURE THAT THE VALVE IS KEEPING COOLANT FROM CIRCULATING THROUGH THE HEATER CORE, CHECK VACUUM SWITCH ON CONRTOL HEAD AND VACUUM BALL ON SIDE OF EVAP CASE. ON MY TRUCK, THE BALL WAS LEAKING VACUUM AND COULD NOT KEEP THE HEATER CONTROL VALVE SHUT, NOW BLOWS DOWN TO 23 DEG, THEN FREEZES UP, I MIGHT HAVE TO TRY A TUBE TO REPLACE POA LIKE WHAT IS IN THIS CAMARO. IT HAS A COMPANY NAME AND PHONE #.
Mark C Jul 3rd, 02, 08:03 AM Sounds like your missing the piece that connects the lower duct work to the upper dash ducts. Its a peice of square plastic tubing, may 3" square with a 45 degree bend in it and it has 2 small circular vents in it. It connects the upper ducts in the dash to the heater box. Without this you won't get any air out of the upper vents.
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Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine (http://www.townisp.com/~markcanning/camaro/transparent%20air%20cleaner3.jpg)
novaderrik Jul 3rd, 02, 08:52 AM i don't think you need to yell to get our attention here. there is a lot of conversing going on, but, really, the background noise isn't so bad we can't all talk in a confortable volume..
or maybe your caps lock is stuck, and your computer is stuck in "yell mode"..
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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
CHEVY TECH Jul 3rd, 02, 01:12 PM sorry about the yelling, the computer i am using is my work computer in my stall, it handles all dispatching of work through the shop and all commands need to have the caps lock on or we get error messages. will correct in the future.
18436572 Jul 3rd, 02, 01:41 PM Is that car back to the dealer for some warranty work? http://www.camaros.net/forum/biggrin.gif
Seriously...the system has to pickup fresh air somewhere.....either through the cowl plenum or through the kickpanel which would be in the recirc position.....I don't know what default (no vacuum present) is for these actuators.....but....one of these vents has to be open for airflow......since the kickpanel vent is screwed shut I would try actuating the cowl vent with a hand held vacuum pump and see if the flap opens....if so You should have some airflow through the vents....
It sounds like some parts are missing.....You will need to see at least an assembly manual.....all My info is for 68....
Everett#2390 Jul 3rd, 02, 06:32 PM ChevyTech, thanks for the advice. Vacuum ball does hold vacuum, coolant valve is new, 2 yrs old, but, I have my doubts. Original problem was the evap freezing up right at start-up. Replaced expansion valve and cured this fault. Owner of truck said cold air really never got cold, <45*.
Let me know in e-mail on the conversion kit replacing the POA valve.
Default position for the air valve in kick panel is open, outside air comes in.
Everett
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