No the check valve is not the PCV. It is probably a one way valve or most probably the vacuum storage tank . This is so it doesn't switch " Modes " under hard acceleration for lack of vacuum .
Thanks for your reply gsx455. What is the vacuum storage tank? I will be needing to buy a replacement one way valve or storage tank. The a/c system is missing those parts apparently. When I got the car the vacuum lines were all cut off at the firewall.
Ed, Do you have a 1967 Buick Chassis Manual? The Heater A/C chapter goes into detail about the vacuum connections and how everything works. I don't believe the 67's use a vacuum storage tank.
Hi Larry, yes I do. I also have the assembly manual. I haven't seen reference to a vacuum canister, so I think you are correct. As far as the check valve goes, here is another diagram with part number, but I don't come up with anything in my searching.
It's a vacuum check valve. Bet you can find a replacement that will work. Just Google it. https://www.google.com/search?client=firefox-b-1-d&q=vacuum+check+valve
I found this but it is out of date http://www.2040-parts.com/65-66-67-...-340-v8-nos-gm-vacuum-valve-1364636-i1832396/
On the earlier cars, like my '64 Riv, they had a round ball that was a storage tank /check valve mounted on the right fenderwell.
