R134a Dryer

Looks like they kept the old receiver/drier. I don’t think it can tell the difference in refrigerant because desiccant is desiccant but I’ll defer to the AC experts on here.

 

I have had several old cars with dryers that were R12 and the system running 134a. I haven't had any issues with this.
The dryer in your picture doesn't need and adapter as long as the compressor has both high and low side adapters already.

 

The fitting is not the issue. I would be more concerned about the fact, that your drier has a glass window (next to the fitting). These were basically useful with old r12, as when you could spot some bubbles, you could tell the system was not properly filled.

Nowadays, these windows are totally useless with r134a so have long been discontinued. In other words You are running your car with a (~20years?) old filter. If the filter breaks, the desiccant can migrate to the compressor and destroy it.

Your car was upgraded to R134, so you probably have a bit of the older oil left in the system. This oil gets hard in the new gas, and can easily plug the filter, so this filter should have been changed shortly after the conversion in order to collect these leftovers.

Finally your system does have a separate pressure switch (the cross section tapped to the drier). This could have been implemented in order to save a few bucks, but on my 400i and other 308 I've seen, the pressure switch is built into the drier, which makes the "plumbing" more elegant.

This part is cheap. See Carl Rose post for Napa cross references (http://www.ferrari.cdyn.com/carl_rose_docs/Ferrari 328 AC Recharge.pdf).

 

Suggested dryer with built-in switch and valve : four seasons 33255 ($15) , given that your system was modified you may need one with two male fittings. In any case your AC shop can provide a cheap proper alternative.

 

raemin is correct. I thought your compressor had 134a fittings. If there are no 134a fittings on your compressor R12 fittings,then you should believe it is not 134a.

 

I would not be so much concerned about the fittings themselves, my own 400i had a mix of old-school "flare fittings", as well as more modern "O-Rings". Others cars I've seen could be flare all around or mostly "o-ring". I thinks the factory did use whatever they had in stock... Flare fittings are slightly more leaky so do not retain perfectly the newer blend of gases that are made of "thinner" molecules.

As far as the recharge port is concerned (on the compressor), whenever a specialist does change the gas he is supposed to put new adapter fittings (on top of the R12 fittings) for the new gas. Easy to source, even on amazon. These are quite ugly... My AC shop never asked for these adaptors to be installed. He just put a label next to the drier specifying my car runs on the newer gas. Your local regulation may be different though.

By the way I am not using straight R134a, but R416 which is R134a plus 2% butane/propane (don't remember which). The additional fossil gas does help dissolve whatever old oil that could be left in the system.

 

The real issue with the dyer is not so much the fittings but the desssicant. Water in the system can cause intenal corrosion problems. An old dryer might not have much capacity to remove water. The old rule-of-thumb is that when you open up the system for any reason, you install a new dryer. It's good insurance to prevent future problems.

 

As a cheaper alternative some do place the drier in the oven, or just aplly vaccum to the system for an extended period of time, both of which "dries" the dessicant.

Water in the system plays havoc with the system as the frozen droplets can seize the compressor. Same story when dessicant escapes from the filter and is swallowed by the compressor.

After so many years, one should consider new filter and even a new condenser expansion valve . Fresh oil in the compressor is also a good idea. After all: the york compressor is a small size piston engine that will last longer with new oil and new filters. Sanden compressors are even more sensitive.