a/c charge in an ls swapped El Camino
06-11-2019, 08:34 PM
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a/c charge in an ls swapped El Camino Good evening folks. Im in the final stages of my lm7 swap in my 72 El Camino. The last part is air conditioning. Im not very familiar with ac systems. I understand how they work and which parts do what but when it comes to charging, flushing and evacuating, I'm pretty much clueless.my question is now that I have drastically altered the ac system, how much do I need to charge it? The vehicle in stock form with r-12 is 60oz, and for r134a it is 45oz. The only stock parts that remain is the evaporator, expansion valve and poa eliminator with TC switch. Im running a denso 10s20f, 16x27 parallel flow condenser and significantly shorter hoses than stock. Am I overthinking this?
06-11-2019, 09:07 PM
#3
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Don't forget to add compressor oil of the type recommended for your compressor - also the correct amount. You can guess here but there are at least three types of oil. After the pump down evacuation, I'd fill based on pressures in the high side and low side versus current outdoor air temperature. There are R134A charts on the Internet for this. Also phone apps. You will need a good set of gauges to do this.
Also, please don't turn your can of R134A upside down with the compressor running for filling your system. This introduces liquid R134A into the system and this liquid is NOT compressible. Only R134A in gas form is compressible. The liquid will possibly hydro lock your compressor to cause severe damage. I keep my R134A upright and then lightly and very mildly heat the can with a propane torch just enough to take the chill off the metal can. This accelerates the fill without introducing liquid R134A.
Rick
Also, please don't turn your can of R134A upside down with the compressor running for filling your system. This introduces liquid R134A into the system and this liquid is NOT compressible. Only R134A in gas form is compressible. The liquid will possibly hydro lock your compressor to cause severe damage. I keep my R134A upright and then lightly and very mildly heat the can with a propane torch just enough to take the chill off the metal can. This accelerates the fill without introducing liquid R134A.
Rick
06-11-2019, 09:09 PM
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The 98-02 Fbody V-8 car takes 9oz of compressor oil and 24oz charge of freon. If the compressor is kicking on and off rapidly it needs more freon. Add it slowly and monitor it but you don't want the compressor kicking on and off repeatedly. My system was leaking and since I had to open it anyways to replace the motor mount through bolts I went back through the system with a new seal kit. Figured its probably time after 18 years but out it all back together and didn't even pull a vacuum on the system and I'm happy to report no leaks and a nice pleasant 47° coming out the vents.
06-12-2019, 03:06 AM
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Don't forget to add compressor oil of the type recommended for your compressor - also the correct amount. You can guess here but there are at least three types of oil. After the pump down evacuation, I'd fill based on pressures in the high side and low side versus current outdoor air temperature. There are R134A charts on the Internet for this. Also phone apps. You will need a good set of gauges to do this.
Also, please don't turn your can of R134A upside down with the compressor running for filling your system. This introduces liquid R134A into the system and this liquid is NOT compressible. Only R134A in gas form is compressible. The liquid will possibly hydro lock your compressor to cause severe damage. I keep my R134A upright and then lightly and very mildly heat the can with a propane torch just enough to take the chill off the metal can. This accelerates the fill without introducing liquid R134A.
Rick
Also, please don't turn your can of R134A upside down with the compressor running for filling your system. This introduces liquid R134A into the system and this liquid is NOT compressible. Only R134A in gas form is compressible. The liquid will possibly hydro lock your compressor to cause severe damage. I keep my R134A upright and then lightly and very mildly heat the can with a propane torch just enough to take the chill off the metal can. This accelerates the fill without introducing liquid R134A.
Rick
I'm running a new Denso 10s20f which came full of Pag oil at the correct capacity. So basically I just need to fill based on psi/temp and established charts?
06-12-2019, 05:44 AM
#6
TECH Fanatic
That's what I would do. You will know you are getting close to the correct amount of R134A when you can dependably control the operation of the compressor clutch with changing the desired temperature setting on your AC system control panel. It's very easy to overfill here so I would sneak up on this slowly with the amount you are filling.
Needing to do this with gauges and pressures reminds me of why I really like AC systems with a sight glass window in the top of the receiver-dryer. If you see a lot of bubbles in the liquid flowing past the window with the compressor operating, you know you are underfilled.
Rick
Needing to do this with gauges and pressures reminds me of why I really like AC systems with a sight glass window in the top of the receiver-dryer. If you see a lot of bubbles in the liquid flowing past the window with the compressor operating, you know you are underfilled.
Rick