[msk1986911]

I had the a/c in my 1986 Coupe converted from R-12 to R-134 last summer by a shop that I trust. I did not have the barrier hoses and all the plumbing; just the R-134 conversion. I was told that the unit held pressure. Also, the initial results were actually pretty good in that it did actually blow cold for a month or so after the work was done. However, at this point, I cannot feel any difference when I rotate the thermostat (knob to the left of the a/c fan speed knob), from the low setting to the hight setting. Also, the receiver dryer does not have a sight class (I assume this is an aftermarket unit) so I cannot determine if the system still has any refrigerant left. Should I replace the receiver/dryer or am I wasting my money unless and until I decide to put some real money into the a/c? Also, is there a difference between the OEM receiver dryers for about $100 and those that I've seen on e-bay for about $30?

I don't know that mileage matters for this topic or not. In an event, the car has just over 75K miles on it

Many thanks.

MK