I have a 78 euro spec 308 GTB with inoperative AC. The picture is as follows: 1. The fan speed switch works (the fans come on at the various selected speeds). 2. The thermostat switch seems to work as I can hear the relay cilcking and the radiator cooling fan come on. 3. The AC compressor however does not engage. 4. There doesn't seem to be any power getting to the compressor. I disconnected the wire at the AC compressor and did a voltage test. With fan and thermostat switches off the reading is about 0.1v, with switches on it is about 0.5v. 5. There is no gas in the system therefore I am not expecting cold air to come through the vents. My concern is that the Compressor is not engaging. 6. In the wiring diagram it illustrates a max pressure switch and a min pressure switch. I am assuming this works with gas pressure and therefore the compressor will not come on if there is no gas in the system (ie. pressure too low). This is just my assumption, I may be completly incorrect. Any suggestion would be greatly appreciated. Regards DIFAZ
Yes, without adequate refrigerant pressure, +12V power will not reach the compressor clutch. If you want to do a short test just to confirm that the compressor clutch would engage if you had a proper refrigerant charge, just connect the two wires together at the min-max switch on the dryer (but don't run the compressor for more than a short time in this condition).
Slight hijack here... I know my system ('78 308) is low. I went to see about having it recharged and was told R-12 is very scarce now adays. I was quoted about $140 to convert to R-134. Sound reasonable? Anyone have this done? Any problems?
Steve is correct. If there is no gas in the system, the a/c low pressure switch will not allow the compressor clutch to engage. This is because it will cause HUGE amounts of wear in the compressor if there isnt any a/c gas/oil being pumped around to lubricate the compressor. So I wouldnt bother with it, until you get it charged up Difaz.
That sounds reasonable mate. All they do is change o-rings on the hoses and compressor oil. Doing that, with labor and add in the 134A gas sounds good to me! Shouldnt be any problems after the conversion, as long as they change ALL the o-rings. R134A runs at higher pressures, which is why all o-rings need to be changed. If you dont change them, you know what is going to happen.
If I were you I would do my best and search hi and low for some R-12.The R-134a will not make your already insufficient A/C system work any better,actually it will make it worse.Do A search on here with regards to R-12 vs R134a.Personally on my GT4 it had R134a already in it when I bought the car.I couldn't get vent temps any lower than 12degC.I sourced some R-12 and went back.Now I get temps around the 5-6degC mark
Thanks Steve & PAP 348. I have performed the check suggested by Steve with ignition on but engine not running and the compressor did engage. Now I feel fairly confident the system should work, providing there are no leaks etc. Many Thanks DIFAZ
R12 is cheaper and more plentiful than it has been in years. I would not dream of converting the system.
Do not convert. R-134 will reduce your 308 a/c to only one mouse farting on an ice cube rather than the two that come OEM.
Right. Only experience I have is Ive done 3 systems.....2 completely. No Ferraris, but, concepts are about the same. Please, do not consider switching to R134a. It is almost useless, and your compressor will work incessantly....... R12 can be had on ebay.....EPA license to buy is easy to obtain, and costs only $25.......If anything, consider Autofrost.
Sadly, R12 is banned in Australia . You cannot get it anymore. The Government have come down REALLY hard in regards to refridgerant handling. You cant buy a/c gas anymore, unless you have a special licence, which is only obtainable if you own your own workshop. You also have to fill out a log book in regards to how much gas you use in each car etc...etc... Tough new laws for a/c gas. We get a "temporary" licence so we can use the stuff at work and work ONLY. The licence is void in the real world. So he HAS to convert to R134A, otherwise he puts up with no a/c.
Wow, good points, pap. Now, are you saying that also Envirosafe (mostly propane) is also illegal to buy/use? Because, this is an alternative to useless r134a. That is what ill be putting in one of my cars this spring.......Envirosafe is colder than even R12, I believe. And no need to panic people, that it is propane. It has been propagandized to death by the DuPonts as a death substitute.......legal in many countries, and no law suits, etc , that I have heard of......
I mean, look, R134a is an alternative IF you, instead of just changing the mineral oil/o rings you: 1) install a bigger, modern/high flow condenser (custom make it, I have heard of some that have done it) 2) get a compresor that will handle the higher pressure 3) get a bigger/additional fan (s) for the condenser THEN, R134a will be worth something. But still wont be as cold as propane.
I dont know mate, have never heard of Envirosafe?? We only use and have R134A here for a/c systems. I was actually diagnosing the a/c in my 'new' ute today with a friend. He actually runs his own workshop with his Dad.
Exactly, bro (down there its "mate", up here its "bro"......LOL) Anything must be done when one's talking about retroing an old ac to a functioning one 20-30 yrs later. AC's a lot of work/expense, as Im sure you understand, so to me, theres no sense wasting effort in just pumping in r134a and a change of oil (which, BTW, is usually never removed completely in a system, resulting in residues of that oil reacting with the chlorine in the new gas, resulting in Hydrochloric acid, I believe). In Florida, like other hot states, AC work is very expensive, and unfortunately, necessary........
Check this out: http://www.es-refrigerants.com/ Again, its the propane idea. AD Little (in the UK), a prestigious research firm did studies on this, and found it to be safe. The propaganda/sensationalism against it is everywhere, so, beware. Maybe your friend has heard of the idea?? Oh, also beware: AC pros are quite against this, since, it is mainly a technicality, I understand (if a state bans it, why "sell" it to your customers)
I had my '86 328 converted to 134....honestly I did not notice any difference... ...I did it because the political landscape is changing & I see the continued crackdown on r-12. Heck, it seems that anything that can be accused of 'global warming' will be outlawed. I know, I know about the mouse exhaling over an ice cube comparison...But in Colorado we don't really have humidity, and if it gets to 90f +... its not really that bad
Thanks for all the input guys. I'm probably going for the conversion, but won't do it until the spring rolls around, so there's plenty of time to change my mind Again, sorry for the hijack.
Don't give up your r-12 system. There are r12 drop in replacements such as HOT SHOT . Check around at an air cond. or refrigeration contractor . We use it all the time for old coolers on yachts.Good luck!
