I've read most of the previous posts on air conditioning, and I don’t think my problem is discussed. My initial problem was my compressor was cycling every 3-5 seconds or so, and cool, but not cold air is being emitted. So I figured my AC was low, and went out and bought a recharge kit that included a gauge. Having lots of mechanical knowledge and NO AC knowledge I figured I could figure it out. Well my gauge reads over 60 with car on, AC off, and with AC on full the gauge rapidly fluctuates from about 25-50 and constantly does this. I've read I need about 40. My instant reaction made me think I didn't have Freon in the system rather something else. Or maybe it’s something so simple I'm missing it. Should I add more refrigerant so it doesn't cycle, or is that two much pressure, or do I empty the system and refill, as I’m sure I have no leak?

Thanks in advance

 

Mine was doing the same thing last summer. I put a can of freon in it (actually the other stuff 134a I think) and it worked fine for a day or two and then did the same thing. I didn't put any more in and ended up having somebody do the evaproator for $1200. If you have the skills you might be able to do the labor yourself. Looks like a lot of work to me, but I will probably try it the next time one goes out on me.

 

So R-12 must be Freon? It was my understanding that the evaporator needed to be replaced if leaking. If my system holds pressure, there must be no leak right, or is there some kind of check valve keeping it under the hood? Ive taken dash's apart before... The only thing making it hard is the fact its finish work, and things need to line back up as apposed to regular wrenching with filthy hands. Its just framing a house vs. triming a house with moulding.

 

Hi Bboble,

Greetings from Yokohama, Japan.

850's A/C is noted for many problems, and I personally feel it's a faulty design (and compressor is most likely Japanese[8D]).

Anyway, like Jim, I added some R-134a last summer as my compressor was turning on/off on its own (it used to turn off when I needed it most). Moderator Tech has a post on compressor re-shimming, and other sources note that the electrical wire on the compressor needs to be bypassed, in order to keep the compressor from turning off when it's not supposed to.

As for the system pressure, I believe the normal pressure was around 30-35PSI. Don't quote me on this, as my memory is vague. But the kit usually comes with a gauge with color-codes and the needle should pointwithin the green band. Be careful of overcharging, it may blow out at the wrong place (evaporator).

As for the refrigerant, R-12 is not compatible with R-134a. If I remember correctly, R-134a is not freon (I believe R-12 is chlorofluorocarbon and R-134a is hydro fluorocarbon, but again my memory on this is vague). If R-12 is introduced in a system that utilises R-134a, itmay eat up the seals and will not provide designed performance. I once had an Accord, and Accord once used 2 different compressors. If the system had Denso compressor, you could empty the system of R-12 and re-charge with R-134a. But if you had Keihin compressor, the system could not take R-134a. I still don't know what the difference was.

If your system is not leaking, the evaporator is probably ok. But in order to get to the evaporator on 850, you can't just remove the dash top, you have to remove pretty much everything and it is a good one-day job.

Anyway, if the re-charge kit indicates normal pressure and the system keeps turning off, you may need to re-shim the compressor or the wire has to be bypassed of the temp/pressure switch. Check to see if the compressor engages if you tap it with metal bar, etc...

I hope this helps.


JPN