I have a 90 suburban the Schrader valve in the high side is non removable and the line is discontinued. Napa can make a new hose with out valve. Can I vacuum from just low side?

  • Welcome to Motor Vehicle Maintenance & Repair! Aug 31, 2019 at 14:40

1 Answer 1


Yes. You can pull a vacuum from one port.

The AC system is a continuous loop. There is a part known as an orifice tube which restricts the flow of refrigerant, but doesn't stop it. Drawing a vacuum from one port will still allow you to completely evacuate the system.

Note: If you are talking about removing either the Low or High side ports and not having it anymore, this isn't a good thing to do. The problem with this is, both ports are needed to properly diagnose issues with an AC system, as well as ensure it is properly filled when adding refrigerant.

  • I did that ; then put one can of Freon in and then vacuumed the system a second time . The AC worked 2 or 3 years until I sold the car. May 23, 2021 at 3:05

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