[satch1967]

1970 Chevelle w/ac




I feel i am not getting strong enough air flow through my vents. The ac is nice and cold but the air flow is just weak.

When I have my ac setting to max, normal, bi-level, which vent's should the air flow through. When I switch between the different settings I do not notice any switching between vents, also ,, I do have a lot of air flow through the floor vent up by the firewall. I know there are some vacuum modules on the plenum box, do you know which one could be bad if that is the issue, also vacuum controlled flapper at the base of the windshield, what is the easiest way to check that to make sure it's not broken. Thanks

 

[Alan F]

You must have engine vacuum to get the air routed through the upper level vents. In a stock configuration it starts at the port on the back side of the carburetor and runs up to the vacuum canister. From the vacuum canister it goes under the dash in to a diverter. There are air doors in the heater box that get actuated to move the air through the upper register. You can get a handheld vacuum pump and lay under the dash and check function. Typically I've seen that the system itself isn't hooked up or deteriorated in some way before the diverter.

 

[satch1967]

Thanks for the information. I will check those items. What is a good place to get a handheld vacuum pump at.


Thanks and keep the idea's coming.. What an awesome site this really is!! D

 

[JWagner]

Over the years, a lot of places in the air system can get clogged up. The A/C evaporator is one place to look. And a lot of stuff falls down into the defroster openings and reduces flow there, too.

 

[satch1967]

I'll check that also. Awesome tips,, I really appreciate it!



D.

 

[Alan F]

I just happen to be working on this on my '69 right now so I'm looking up stuff for myself anyway. Here's a diagram of the flow. It also names which levers control which doors. Some are vacuum and some are cable. Again, this is for a '69 which is close and should only be viewed as representative.

 

[satch1967]

WOW !!! Thank you so much for the diagram. This real helps as a respective of how things are supposed to work.

I am truly amazed this is such an awesome site and so helpful,, everyone here rocks!!!!



D