63 riv Happy Saturday and AC Questions

[Guest Steeleco]

Well the weekend is finally here so us poor working stiffs can work on our cars (great fun!). Obviously the newness of this has not worn off for me.

Here are a couple questions about the 63 riv AC system:

1. According to the Buick Chassis Service Manual (page 11-49), the STV valve allows Maximum cooling when no vacuum is applied and minimum cooling when 6 to 7 inches of vacuum is applied. Although this is backwards from other Buick models of that year is the manual correct or did they get it wrong? (hope I worded this right)

2. As my AC is working fairly well my other question is this: When using Max AC how do you adjust from outside air to re-circulate air?

Thanks and have a great day.

[Jim Cannon]

1. The manual is correct.

2. The switch to RECIRC should happen automatically when you push the AIR and COOL knobs fully in to get MAX cooling and all heater knobs OFF (both need to happen). Note that with the stock setup working correctly (vacuum being applied only to the lower vacuum can under the fan motor box), MAX cool RECIRC is only 75% recirculation. You can modify that to 100% recirc by removing and plugging the lower vacuum hose down below the fax box. You should confirm that it is the one that has vacuum when AIR and COOL are both on MAX. Over the years many of these vacuum hoses get moved around by people.

Follow the adjustment procedures in the shop manual on page 11-80 to make sure all the little vacuum switches are set correctly, to get the vacuum to where it needs to be in each heating or cooling position.

[Guest oakland]

I adjusted the vacuum switches as per manual on my 63 Riviera, but I do not get AC air out of the air vents in the dash, only from the heater vents. If I by-pass #1 switch the air comes out of the dash as it is suppose to. I changed the #1 switch, thinking it must be bad, but it is the same thing. Any suggestions????

[Jim Cannon]

Well, when you have the knobs set for A/C, you need to confirm with a vacuum gauge that you have vacuum going into switch #1 and coming out of it, AND make sure you have vacuum going in and out of switch #3. You need both.

Are you sure what you are calling switch #1 is really #1? It is the vacuum switch that is all by itself on the engine side of the control unit.

Make sure you don't have the lines going to the vacuum actuator up on the firewall reversed.

Make sure the heater is OFF when you are testing A/C.