I can share a little information from my experiences with A/C's. First the freons. R-12 works very well, but is too expensive and may be associated with ozone layer changes. Two years ago I converted to Freeze 12. It worked well. On GM vehicle it required the thermostatic pressure switch be lowered to a slightly lower pressure (20 psi) to give the same cooling. I drained what oil I could from compressor and added 3 fluid ounces of Ester refrigerant oil. The mineral oil used with R-12 does not transport thru the system with Freeze 12 or R-134a, but the addition of Ester oil solves this problem. I heard one person used Freeze 12 to add to R-12 system, WRONG--- It is a total replacement, not partial. Freeze12 is a blend of refrigerants and as such must be charged as a liquid (upside down can), otherwise it would be possible to get only one of the fractions (whichever evaporated from mixture first) into the system. The drums of Freeze12 have a bottom pickup tube so don't turn them over. Use 10 percent less refrigerant, i.e. a 4# R-12 system would use 3.6#. Freeze 12 is 80% F-134a, so I used F-134a in the next two systems I did, and both were quite satisfactory. I couldnt drain any oil from those, but Ester addition did the trick. Freeze12 has a lower high pressure than R-134a, but 134a has not been a problem for my vehicles. Conversion kits are readily available with Ester oil and refrigerant, and adapter fittings to prevent R-12 being accidently added later. Installing the adapter fittings requires hose adapters, or special hoses for the gauge-set to be used. FR-12 is a different mixture which I do not have experience with. FREEZONE is like Freeze 12 except is 79% F-134a and has 2% lubricant, the remainder being HCFC-142b in both. Don't know about R-409. An excellent web site for auto A/C is http://members.tripod.com/~jbabs714/autoac.htm . You have had far too many failures of the A/C, has to be a problem? Check the condenser in front of the radiator and check for bent fins and bugs down in the fins, I know mine has many bent fins (can't comb this type out), which causes higher pressures and temperatures. Regards, Paul ----- Original Message ----- From: To: <1winne_h-bodys@o...> Sent: Sunday, September 19, 1999 6:40 PM Subject: [1winne_h-bodys] Air Conditioner > From: hitected@s... > > Hi all- > I was just wondering if I am alone in my problems ??? > It seems most of my troubles are a/c related. If we > don't use our a/c while traveling, we have very few > problems, but turn on the air and wait for it to happen. > We have lost freon several times; twice the hose came off > the compressor, twice the compressor froze up & once the > fitting (low side) broke (none available) replaced with a > modified fitting from winnebago. I have been using R-12 > freon until now, my supply has ran out. I have heard of the > following substitutes: R134A, FR-12, FREEZE-12 &R409A. > Which is best ?? What would be recomended now ?? > Ted Pitts of Orem, Utah 83LSTD hitected@s... ADVERTISEMENT In a message dated 03/15/2000 4:09:20 PM Central Standard Time, leocor@m... writes: > Arch, how > is your switch jumped out. Can you explain it? Can anybody else shed > any light on this? Leo You are now into one of the nightmare systems on the LeSharo. My pressure switch has 2 wires coming out of it both brown with a white stripe. If you have the grill off you will see a row of sensors down the passenger side of the condenser. IIRC there are 3. All of these sensors have to be satisfied before the AC will work. One is a high pressure cut out. One is a low pressure cut out. And one is the switch that turns on the fans on when head pressure reaches 350 PSI. Trouble shooting is real fun. I have replaced them all. I have had more problems with the connections to the sensors that the sensors themselves. I cant tell you exactly what the connections are but I will bet they are in series. Just a thought. Take Care Arch Hi, The most common problems we find on A/C is the lack of knowledge by your service technician. Any contamination or particles in the A/C system will damage and probably seize the compressor. When the compressor seizes the belt keeps turning the engaged A/C clutch and ruins it. Items to check. 1. The A/C filter-drier is located in a panel behind the passenger seat. This MUST be changed when installing a new A/C compressor. 2. While the A/C system is open you MUST flush the ENTIRE system, all of the pipes, hoses, evaporator, condenser with the filter-drier out. We use NAPA - DURA 141 A/C Flush-Solvent. 3. Use the proper amount of the proper oil per the manual. Now is a great time to retrofit to r-134a Freon (its less expensive but does require new 'o'rings throughout the system, a flushed and clean system, a different oil (PAG) and the new Freon. Now, a different thought. The A/C clutch MUST have the proper clearance between the engagement plate and the electro-magnet or it will not release. The overhead switch may be faulty and not breaking the electrical connection BUT if the compressor is working properly there should not be a problem here. If the pressures in the compressor are too high the clutch may slip and ruin the friction mating surfaces. Just some ideas to start with. I have good used A/C compressors here and I can provide part #s for locally sourced items including the filter-drier. Regards, Greg Greg Erickson S~works RV Inc. Bozeman, MT Hi everyone, I just converted my dash air unit in my 1989 LS 2.2 Gas from R12 to R134A. When I got it the line to the evaporator was broken and I got a new one made for $50 and put a new dryer/accumulator on it. I flushed out all the lines and blew everything out with shop air. Here is my question... I couldn't find out anywhere in the manuals that states the capacity of the system as far as freon or oil. www.sanden.com has a great manual for servicing the SD709 conpressor and explicit directions for the R134A retrofit. It says that the compressor is to be charged with 4.6 oz. PAG oil but of course doesn't take into account the rest of the system. I put in a 8 1/2 oz. oil charge that also had a o-ring conditioner built in and four pounds of R134A. This got me down to about 58-62 degrees but according to the pressure readings, I still don't seem to have enough freon in the system. Does anyone know what is called for as far as a full charge? Thanks, In front of the right side back passenger seat in the "flare-out" area, there is a removable panel with the receiver with an old fashioned sight glass on my 88 gas unit. As I recall from 40 years ago, add until the bubbles go away and the rest of the can. Probably not exact but the space in the receiver will probably accomodate at least a full can. If you are using a full set of gauges, add until the pressures stabalize on a hot day. What pressure readings are you using. I do not have a set of gauges calibrated for 134 so cannot help. When using F-12 long ago, you could normally get it to a point where the suction side corresponded to about the freezing point of the 12. With much less than that you would get coil freezup. If you already have charged the unit, and there are no bubbles in the sight glass, you probably have AT LEAST enough and hopefully not too much. If it sounds like the compressor is knocking, probably too much. Hopefully you had the equipment to pull a good vacuum or at least purged the unit with 134A after blowing it out with shop air. In the 60's, there was an outfit called "Comfy-Kit" that sold add on units and the procedure was to purge with one can, then add two cans for a unit with only one evaporator and short hoses. Four cans sounds like maybe a lot.