How do you locate the AC low side port on a 1979 Buick Riviera?

To locate the AC low side port on a 1979 Buick Riviera, open the hood and look for the AC compressor, which is usually on the front of the engine. The low side service port is typically on the larger diameter line connected to the compressor and is often closer to the firewall. It will have a cap that may be black or blue and is designed to accept a refrigerant charging hose. Be sure to consult the vehicle’s service manual for precise location details if needed.