Since it's almost spring and my engine is about to be all back together...it's time to turn to my A/C system and get it running well again. It's currently the original setup but missing a few things when I compare my car to the original drawings of the '69. It's missing the Dehydrator and the Muffler (bolted right up next to the compressor).
Being all original minus those parts means that it is still R12 which is very expensive.
1)Should I change over to R134? 2)If I switch over would this be a noticable change that would look much different from the R12 system? 3)My mechanic who would do the work says that to make the switch he'll just put different nipples on so that the R134 hoses will connect to the system...is it really this simple? 4)Can I leave off the muffler and the dehydrator or should I find them and put them on?...I haven't seen a muffler anywhere, but I'd like to get one just so that it looks original.
Dan. When I put mine back together I pondered the same things. I talked to a tech down in Florida who worked at an a/c shop. He said he converted his 69 to 134 and he wasn't happy with it. He said he didn't think the condensor had enough surface to cool the 134 right(?) I just put mine back with r-12. I sent my muffler and poa valves out to be tested and I had the muffler replated. The system works very well.
i have done very little a/c work, but worked in a shop which had a bit of a/c traffic. i'll relate what little knowledge i may have gathered, hopefully accurately.
like bweber, we seemed to have quite a few cooling complaints from r134a customers, whether their car came with it, or it was retrofitted. it just is not quite as good of a refridgerant, especially if the car is not moving.
when you retrofit an older system, sometimes you need to change the hoses too, because the oil soaks into them, and r134a and r12 oils are incompatable. the hoses start to fall apart, and destroy the system with particulates, or leak.
there are other refridgerants besides r12 which you can put into an r12 system. the most common is brand named Duracool. check on local and state laws before you do. it is basically lighter fluid, which sounds scary, but it is no more dangerous than other refridgerants, a fuel tank, or a battery. your windshield wiper fluid is highly flammable too.
but the answer to question #3 would be 'yes' it can be that simple. but you should also have a sticker stating which type of refidgerant is in the system.
i dont know specifically about the muffler and dehydrator, but i believe the dehydrator should be replaced with a new part if it has been open to the atmosphere. at least that is what i've been told about receiver/dryers. perhaps the dehydrator is serviceable. the whole system should also be drawn under vacuum for several minutes to help remove moisture.
if you do switch to r134a, it cools better with the system not filled to capacity. i am not sure, but i think 80% or thereabouts gives the best cooling on a retrofit. like if you have a 2lb r12 system, you would only put in 1lb, 12oz of r134a and oil.
your mechanic should know most or all of this stuff anyway, because most states make you take an epa test just to handle freon for buying and selling, and then for servicing, you need to be certified anymore. the certification tests include all the info+ which i just related, and more accurately, i'm sure.
Never did mine myself...but have converted 3 systems from R12 to R134....they all worked better afterwards ,but you gou to do the whole system and do it right.... Not sure how close to orig. it will look , since I never did a GM car....(it was Volvo and Ford)
