The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1971 Factory Air Conditioning Hot/Cold Lever

Andy4639 · 09-01-2015, 04:26 PM

If you take the cowl off you will see the flapper. It keeps outside air from entering the cab through the blower Motor. I have sealed mine off totally and took the vacuum line out. My AC runs great. It's on what the late models call MAX AC, not blend which is what you get when you have the flapper hooked up and operational. If the vacuum is not working correctly it will open and let hot outside air in + if it's all the way shut it's not a perfect seal. In other words your always adding fresh hot outside air to the AC system with the flapper opened any at all.
Just for good measure I have a manual hot water valve in line on my heater core to stop all water flow through the heater core. Any hot water coming through it to the cab will keep the temperature up inside the cab.
Here is another post we talk about it.

http://67-72chevytrucks.com/vboard/s...d.php?t=253275

09-01-2015, 04:26 PM	#5
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: 1971 Factory Air Conditioning Hot/Cold Lever If you take the cowl off you will see the flapper. It keeps outside air from entering the cab through the blower Motor. I have sealed mine off totally and took the vacuum line out. My AC runs great. It's on what the late models call MAX AC, not blend which is what you get when you have the flapper hooked up and operational. If the vacuum is not working correctly it will open and let hot outside air in + if it's all the way shut it's not a perfect seal. In other words your always adding fresh hot outside air to the AC system with the flapper opened any at all. Just for good measure I have a manual hot water valve in line on my heater core to stop all water flow through the heater core. Any hot water coming through it to the cab will keep the temperature up inside the cab. Here is another post we talk about it. http://67-72chevytrucks.com/vboard/s...d.php?t=253275 __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.