1990 Mazda Miata converted system R12 to R134

Tiny
WARRENJ
  • MEMBER
  • 1990 MAZDA MIATA
  • 4 CYL
  • 2WD
  • MANUAL
  • 136,000 MILES
My compressor cluth locked up. So in replacing the compressor and clutch as they are one pc we converted to R134 since the compressor came loaded with 134. Found hole in evaporator and replaced it along with Receiver dryer and expansion valvle. Does not cool below 52 and seems to go between 52 and 56 depending on ambient temp. ANy ideas as to what could be wrong.I was told the conversion would be slightly less effecient but not really noticeable. But now we are all scratching our heads as to how to resolve the problem
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Tuesday, August 26th, 2008 AT 5:05 PM

5 Replies

Tiny
MERLIN2021
  • EXPERT
You changed ALL the oil? This uses PAG oil, not compatable with R12. And do not use the same amount of R134 as R12, use less.
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Wednesday, August 27th, 2008 AT 3:47 PM
Tiny
WARRENJ
  • MEMBER
Yes the system was vacumed down and then filled with appropriate oil and freon. I will have to double check the amount of Freon used.I know the pressure were reading right the first time. We vacumed out the system again and refilled it.I have to double check but one of the techs mentioned he thought the pressure readings were not where they were supposed to be. We even changed out the compressor under warranty to see if that would fix the problem but it is cooling even worse than before
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Wednesday, August 27th, 2008 AT 9:54 PM
Tiny
MERLIN2021
  • EXPERT
Try replacing the reciever/drier, and the expansion valve. Low side sould be 30-40 and high 150-200 on an 80 degree day.
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Thursday, August 28th, 2008 AT 12:54 PM
Tiny
WARRENJ
  • MEMBER
Yes all components except the condenser have all be replaced and the compressor twice. We are thinking of vacuming down the system and trying R12 as that is what the system was designed for. Any othe ideas as to why the R134 wont work. Do you know anything about the product Freeze 12 they tought it as a better replacement for R12 than R134.I assumed it was a marketing gimmick and really R134 in disguise. What are your thoughts
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Friday, August 29th, 2008 AT 2:26 PM
Tiny
MERLIN2021
  • EXPERT
R12 is not sold in the USA anymore. Freeze12 is not R12. Expansion valve in the evap core may need to be replaced. Call Mazda to see if it needs a different valve than the stock valve. Do you have the h & L side readings?
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Saturday, August 30th, 2008 AT 3:43 AM

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