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Car Forum / Ford / Ford Trucks / June 200592 F250 AC problem
I reciently had a shop convert my AC over to the new R134. It worked for about an hour then stopped. 2 days later it worked fine for two days and now it stopped working. Is there some sort of a relay or something that would cause this to work, then not work.....? > I reciently had a shop convert my AC over to the new R134. It worked for > about an hour then stopped. 2 days later it worked fine for two days and > now it stopped working. Is there some sort of a relay or something that > would cause this to work, then not work.....? Pressure is probably wrong. Take it back. >> I reciently had a shop convert my AC over to the new R134. It >> worked for about an hour then stopped. 2 days later it worked fine >> for two days and now it stopped working. Is there some sort of a >> relay or something that would cause this to work, then not work.....? >> > Pressure is probably wrong. Take it back. Would not having the correct amount of freon in the system cause it to work sometimes and not other times? >>>I reciently had a shop convert my AC over to the new R134. It >>>worked for about an hour then stopped. 2 days later it worked fine [quoted text clipped - 5 lines] > Would not having the correct amount of freon in the system cause it to work > sometimes and not other times? Yes, depending on the underhood temp. >>>>I reciently had a shop convert my AC over to the new R134. It >>>>worked for about an hour then stopped. 2 days later it worked fine [quoted text clipped - 6 lines] >> work sometimes and not other times? > Yes, depending on the underhood temp. I don't think the R14 system uses freon.I'm not an expert though. Geoff. >>>>> I reciently had a shop convert my AC over to the new R134. It >>>>> worked for about an hour then stopped. 2 days later it worked [quoted text clipped - 10 lines] > I don't think the R14 system uses freon.I'm not an expert though. > Geoff. I am not either. I meant the R-134, but I thought it was also called freon, just a different formula. Sorry for my lack of knowledge. >>>>>>I reciently had a shop convert my AC over to the new R134. It >>>>>>worked for about an hour then stopped. 2 days later it worked [quoted text clipped - 14 lines] > I am not either. I meant the R-134, but I thought it was also called freon, > just a different formula. Sorry for my lack of knowledge. They are both refrigerants. Retrofitted systems are a hack unless they are done right. Very few people do them right. The pressures are different for R134 and R12. Systems designed for R12 often work poorly and/or fail soon after the retrofit. R134A is a refrigerant, and a replacement for R12 Freon. It operates normally at about 10% higher pressure, and at about the same percentage less efficiency as R12. What JimV was referring to is thermal expansion, which causes the base pressure in your system to be higher in the engine compartment, due to ambient and engine temperatures. Your system has a low and a high pressure safety switch, to protect the system from damage as the pressure increases past a predetermined point. It is common for a garage to overcharge the system when performing a retro-fit, because it doesn't take quite as much R 134 as it did the R 12. .....in any case, follow JimV's advice, and take it back. Spdloader >>>>>I reciently had a shop convert my AC over to the new R134. It >>>>>worked for about an hour then stopped. 2 days later it worked fine [quoted text clipped - 9 lines] > I don't think the R14 system uses freon.I'm not an expert though. > Geoff. >R134A is a refrigerant, and a replacement for R12 Freon. It operates >normally at about 10% higher pressure, and at about the same [quoted text clipped - 13 lines] > >Spdloader Actuallly R134a is not reallya replacement for R12 in R12 systems it is just widely availble that all and easy to market because of lack of restrictions. R134a has different boil temps and heat absorbtion than R12 and the reason you use less charging is because it is to keep pressures lower because a new system designed for R134a runs at about 15 to 20% higher pressure than a R12 system was designed for to boost efficency of R134a thru greater expansion when cooling. You must evacuate system of R12 and you really should drain and replace oil in system (replace receiver dryer too) because R12 oil IS NOT compatable with R134 and they add a oil to system to "bandaid" it together and make existing oil compatble with R134a. The trouble with this is that sometimes it leaves too much oil in system which can lead to higher pressure and shorter compressor life. Yes people do convert without a complete purge with mixed results but is you want max cooling and long life, drin all oil from compressor, replace dryer, add new correct oil and vacum down system to reove moisture and traces of R12 and then recharge system. If your A/C was marginal when car was new, with R134a it may do badly but if it cooled with power to spare with R12, it should do okay with R134a. For the record there are a lot of R12 subsitiutes that are more compatable with R12 systems and their oil and the R12 itself. >I reciently had a shop convert my AC over to the new R134. It worked >for [quoted text clipped - 3 lines] >that >would cause this to work, then not work.....? When you say it stopped do you mean stopped cooling, the compressor stopped running or what stopped. R134a will hits higher pressure on a warm day than R12 will and can cause a over pressure kick out on some systems. Most conversions go fairly smoothly but some do not as R134a does have a diferent pressure curve than R12 and is a marginal replacement at best in a system desigened for R12. If compressor does not run, check charge pressures to see if they are too high (or too low) In a conversion you want to error to a slight undercharge with R134a in a R12 system, not a overcharge. >> I reciently had a shop convert my AC over to the new R134. It worked >> for [quoted text clipped - 13 lines] > low) In a conversion you want to error to a slight undercharge with > R134a in a R12 system, not a overcharge. When it stopped, the vents stopped putting out very cold air. The AC air was the same temp as the vent air, using a very scientific process involving putting my hand in front of the vent to check. The compressor was kicking in a out like it should, however it seemed to me that it was kicking in an out a bit more frequently. It seems to work when it is warmer outside than when it is cooler out, over 80 degrees F. Take it back. Spdloader >>> I reciently had a shop convert my AC over to the new R134. It worked >>> for [quoted text clipped - 23 lines] > It seems to work when it is warmer outside than when it is cooler out, > over 80 degrees F. > >> I reciently had a shop convert my AC over to the new > R134. It worked [quoted text clipped - 38 lines] > cooler out, over > 80 degrees F. Try changing/upgradin the cutout switches. There is shrader valve under them to prevent freon loss. Does sound like it might be just a bit under charged though. If it was overcharged it would kickout prematurely in hot weather. :: "Treetop" wrote: ::: SnoMan wrote: [quoted text clipped - 46 lines] :: bit under charged though. If it was overcharged it would kickout :: prematurely in hot weather. I finally got a chance to take it back to the Mechanic. He checked for leaks and drained and recharged the system. He took it out for a few test drives and worked for him just fine. I picked it up. It worked for about 5 miles. While driving home and thinking of finding a new mechanic, I turned the temp to hot for a bit then back again and it worked the rest of the way home. Is there such a thing as a faulty temp switch? Is it something that I can replace? |
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