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bobval
26-02-2014, 07:44 AM
Hi all
I'm back, what a bore!. Ok have exhausted the dual Keihin carburetor saga MKRS from Adelaide has with, what turned out to be, an EG model Civic. Different setup entirely from an ED3. I still say give the Techron 5000 solution a real tryout, up to a month or so to get a contaminated fuel system clean. This blurb is about air conditioner service? You can not service an AC system, all ac are fully enclosed, nothing can leak, nothing can degenerate other than by actual fault. So it is a repair, not a service that is needed should the cursed thing not create a cool air flow into the cabin. The first and only test the home owner can and should do is stick an accurate probe type thermometer into the central dash air outlet, run the ac at full cold, fan rate 2/3 all windows closed, and drive for at least ten minutes or at least until the engine is at operating temperature. The human body is not a thermometer, warm to some is cool to others, we need math here, not emotional feeling. Right! the ambient air temperature and current pressure must be known, the car is then parked in full shade with absolutely no sunlight striking window glass, and no hot wind either. Your beloved Matsushita ac compressor is a vane type, designed for low power engines in the 1980's. Today's ac compressors are vastly more efficient and variable displacement designs. Small ac compressors equals minimal cooling so do not expect miracles. No ac of any size must operate below about +4 deg C, the risk of freeze up at the evaporator would be too high otherwise. All said an ac converted from R12 to R134A should produce an outlet temperature between +5 (ambient below 12 Deg C) and +7 deg C at ambient around +20 deg C with perhaps as high as 10 deg C at 35 deg C. Do not freak over an ambient higher than 35 deg C, a cabin at 30 deg C with OAT over 40 deg C is bloody marvelous. The ac is a cooling device not a refrigerator, the human body is comfortable in the 18-24 deg C range, achieve this and you have no problems, irrespective of ac workshops cajoling you into what is alleged as a, service? All that can be done to an operating ac is to do a needless pressure test, a complete evacuation of the existing R134A gas (in liquid form) and then recharge the whole system, attach an R134A recharge sticker, and Bob's your uncle! after forking out anywhere between $150 to $500. Buy lottery tickets or plunge on the horses, better value. An ac will fail rapidly once seals, O rings or pipes begin to leak R134A, a compressor failure is immediate, you will surely hear and recognize this type of failure. Sorry folks, ac repair is a different kettle of fish, this is not a service, count on at least $1000 sitting in the bank before considering a full overhaul. Car ac should run faultless for at least 15 years, mine has already lasted 23 years and is OEM specs. The R134A conversion seems to have been done in 2010, no pipes, seals, o rings or receiver filter was changed. I was informed yesterday by a licensed AC fitter that this the normal procedure for older cars during conversion, if no leaks in system, and OEM specs under R12 are right, leave it alone, just a full 1 hr R12 evacuation, fit R134A service valves over the existing R12 threaded valves, set them in locknut and replace R12 with R134A refrigerant to the exact quantity using a PG oil, attach the conversion sticker by law. Total cost around $200. Hopefully you will now have a fully tested ac good for another 15 years, maybe! Do not get sucked in to a waste of money, if the ac feels cool enough for you, just make sure you run it at least once a week, winter and summer. Very few cars will still be running working ac under R12, if a 23 year old R12 system fails, just open the windows.

bobval
28-02-2014, 06:54 AM
I cannot nominate the Matsushita aircon compressor model number, the whole thing is located below inspection from above. However all Honda Civic ED3 models manufactured for OZ with JDM specs were fitted with Matsushita, most USA ED3 Civics also had a Sandford. I think the USA and Europe converted to R134a before OZ. My post is only directed towards JDM OZ released Civic ED3's, no other model or compressor. I also specifically nominate units converted from R12 to R134, there is a slight loss of cooling efficiency in the change over. R134a systems run at higher pressure and contain less R134a refrigerant by about 20%, to accommodate the OEM R12 systems pressure limitations using the original seals, O rings and evaporator. 10 years of R12 to R134a operation has not revealed any inadequacy in OZ in retaining AOK original components. The Yanks would have the hapless owner change everything for no good reason. Initially they overcharged the R134a and caused O ring failure. Look up the actual OEM specs for an operating Matsushita system running under R12 in the graph on page 15-56 in the English workshop manual. Consider allowing about 2 deg C increase in OEM specs for delivery temperature at nominated air intake temperature. Forget about intake pressures and delivery pressures, you have no means of measuring those. Accurate monitoring of my 23 year old Matsushita R134a converted system has consistently recorded +5 deg C at the cabin central dash outlet at max cooling set and fan speed 2 all the way up to around an air temperature intake of 18 deg c at the radiator whilst travelling at 60 kmph. Stationary in the shade at 25 deg C, I generally record 7-8 deg C at the dash air outlet. At 40 deg C and we had quite a few of those days in Canberra this summer I think the compressor just kept doing it's thing and pounded out dash air at 10-12 deg C. Can't do better than that! Actual cabin temperature, well that's a different kettle of fish, one person, furnace like sun, surrounded by glass, hot engine etc, etc, one would be lucky to sitting in 30 deg C air. I did resort to opening the window at start up to ventilate the hot cabin air. My parked car on the supermarket lot was well into the 50's deg C. I have never seen condensation water dripping from the evaporator after parking, at 10%-30% humidity in Canberra, there is no humidity to condense. Now I have a lot of respect for what I thought was a piss poor ancient air con system, only big 6's and V8's can run large enough compressors to maintain air at 18 deg C in the blazing desert like conditions of a Canberra summer.