Automotive Air Conditioning Information Forum (Archives)

r_2016 on Tue May 05, 2015 8:49 PM

Year: 1993
Make: Cadillac
Model: Deville
Engine Size: V8
Refrigerant Type: R12

I need to replace the service port on the low side of my ac system, it looks like the valve on the service port is broken so when I try to attach the hose with the fitting on it, it will not make a connection. The service port on my car unscrews from the low pressure line; I would say that it is about maybe 1/2-3/4 high and has threaded ends on both sides; one side is the side that accepts the R12 service hose and the other side screws into the low pressure line. I am going to wind up vacuuming out the system, replacing all the o-rings anyway so I figured I would replace the high pressure service port too, that is the same type of setup except I believe that one the connection is a little bigger. Does anyone know what these are called and if they know of any places where I could find them? The car is a 1993 Cadillac Deville. Thanks for the help

mk378 on Tue May 05, 2015 10:50 PM

On later model R-12 cars the smaller port is the high side and the larger one is the low side. GM also introduced a recessed valve design for the high side to further thwart people from connecting cans of R-12 to the wrong port and having the can explode.

To connect the red hose to the high side port on such a car you need an adapter such as part # MT0436 in the middle of this page:
http://www.ackits.com/mastercool-service-tools-and-equipment/service-port-charging-adapters-mastercool