A/C system type identification
 

is there an obvious way to tell if my '86 A/C was or was not converted to R134?

Normally you will have some screw on fittings for quick connects on the compressor ports. If it was converted correctly..

If the job was done correctly there would be a light blue label in the engine compartment noting it was converted to R134a.

On your compressor's hose manifolds there are to 'service ports' sometimes referred to as 'schrader valves'. Usually these ports have plastic caps on them.

If you remove the plastic cap, on an R12 system the service ports have threads on the OD of the service port stem and they resemble a common bicycle valve stem, and the OD's are the identical size.

On an R134a system the threads are on the ID of the stem, and the outer diameters are different sizes, larger is the high side and smaller is the low side

And you have other places that might advise you of repairs or upgrades, such as service records, work orders, invoices, etc.

THanks guys
 

exactly what I need to know. We'll check it out.