When I swapped the engine in my Yellow Mav I disconnected all the A/C hoses to make thinks simpler ... Today I filled the original R-12 system with R-132 I bought as a kit. I just took it out for a test drive. A thermometer in the center A/C vent registered a cool 40 degrees .... cost me $34 for the kit at Wally World ... :bananaman
to make a older system last don't fill a r12 system with the same amount 134....... 134 is a lot hotter ...i have had best luck it calls for 3lbs r12 i put 2 1/2lbs 134
The kit I bought has a pressure gauge on the hose and I filled it to around 27 PSI ... the manual said to fill it between 25 and 45 PSI but it is cooling fine on the lower pressure.
Does it have the oil that is supposed to be added to a 134a system (I can't remember what it's called)?....
The OIL is pre-mixed in with the R-134 ... Here is the kit Wal-Mart sells ... http://www.id-usa.com/product.asp?CID=28&PID=218
What was your outside air temp? From what I've seen, 134 in a 12 system works OK until it gets nice and hot outside and your idling at a stop light.
A/C service guys call those kits "death kits" since many times the result is "death" to your A/C system due to the compressor seizing, etc. I am not an MVAC guy by trade or anything, but I have done quite a bit of tinkering with car A/C systems over the years. (I have a refrigerant recovery machine and have a 609 cert. so I can buy cans of R-12) I have used those kits to convert a couple cars in the past few years and neither one resulted in compressor death. Some cars are better conversion candidates than others and I have been told that Mavericks usually do OK. I can tell you that the performance of the A/C was not as good as R-12 and indeed really hot weather and sitting at idle will cause center vent temps to go up pretty quick. The biggest thing you need to do for a successful conversion is to vacuum down the A/C system before charging it. Most people don't because they don't have access to a vacuum pump. If you don't do it, performance will suffer and there will be a bigger chance of compressor failure. This is because the air trapped in the system is non-compressable and will result in higher than normal head pressure in the compressor. R-134a already will result in higher pressures than R-12, so this is not good. Also, higher ambient temps result in higher head pressure, so when one day when it is good and hot out you might get SCREEECCCCH....BOOM! Definitely not good! Another trick to get the most out of an R-134a conversion is to consider replacing the factory condensor (in front of the radiator) with what they call a "parallel flow" condensor. Instead of a flat tube that snakes its way from the top of the condensor to the bottom a parallel flow one has all the horizontal tubes connected to a vertical tube at each end. Apparently this design is more efficient than the old style and will help compensate for R-134a's heat transfer shortcomings. As far as oil compatibility, this seems to be debated back and forth, so in the conversions I have done I simply did what the instructions called for and that seemed to work. I currently run R-12 in my Mav since I wanted the A/C to work as well as possible...and I am able to recover and reuse it if I ever need to take the system apart. A little more than my , I guess.
I've never had any problems converting a system over to R 134 as long as I flushed the system first. The rotary type compressors are real subject to failure if you don't flush the system real good, but the york style seems more forgiving. I made a vacume pump from an old deep freezer compressor, an old refridgerator compressor will work also. Just hook up the vacume side thru the gauges to the low presure side, pull a vacume about 30 mins, shut off and check to make sure the system holds vacume. If no leaks, charge system and enjoy cool air!
Down here in Houston, we don't need no A/C When I took my 30 year old compressor and tubes off (for extra space, and I don't want to lose any of my 98 horsepower to no A/C compressor ) it still had some pressure on it, so maybe the compressor is still good? Either way, I know the condenser is good, and a new compressor was only $100 at O'reilly. I figured a new A/C system after everything else is completed. Being in Houston, that is STRONG encouragement to get it done as quickly as possible, which I am not doing
A local repair shop was gonna purge and fill my system with FREEZE-12 for $140. I see Freeze-12 online and on eBay but no place locally had it ... I wasn't gonna pay a shop $140 for $20 worth of Freeze-12 ...
Freeze 12 is 80% R134 and 20% R12 according to a web site I found(and they say you cant mix the two), Id have to really dig to find it again. Ive tried R134 and Freeze 12, but had the best luck with hc12a and envirosafe, which are basically scented propane. This is widely used in other countries, but not accepted here in the US. Check out this site about 134, of course it was probably done by a very biased person, its still interesting.....deadly134.com
