- Background
- My van is 2008 Ford E350 XLT Super Duty, 5.4L V8 Gasoline engine. The air blows but not cold at all. The AC compressor turns on once in a while. If engine is off, I can still use my hand to turn the clutch, it’s not stuck.
- https://www.facebook.com/reel/1231186285585943
- I used the charging tool bought from O’reily, based on its instructions it seems it’s charged, but in reality it’s not.
- tools needed
- R134A A/C Manifold Gauge
- Vacuum Pump
- R134a Freon.
- Kitchen weight scale
- a short wire
- procedure
- turn off the valve for lower and high pressure, near the Manifold gauge and near the connectors.
- connect middle yellow tube to vacuum pump. fill in enough pump oil, remove the top cover while running the pump. turn on the pump.
- open the low pressure value near the manifold gauge(blue), then the high pressure valve near the manifold gauge (red). this is to extract the air from the tubes.
- turn off both high & low pressure valves near the gauge.
- connect blue tubes to low pressure charging connector on the car, red to high pressure. pull it up a little bit to make sure connection is good.
- turn on the valve near the connectors for high&low pressure.
- turn on the low pressure valve near manifold gauge. if you see non zero pressure, that means there’s still some freon in the system.
- connect yellow tube to freon recycle machine. turn on the low pressure valve on manifold gauge.
- Notice: don’t release freon to air, it’s illegal and bad for the environment!
- turn on the high pressure valve near manifold gauge.
- turn on vacuum pump to pull out the air. until low pressure gauge shows -30. keep vacuuming for 10min.
- turn off valves near manifold gauge for high&low pressure. wait for 1 hr, see if pressure changes from -30. if so, there’s a leak in the system. if not, proceed.
- start vacuuming again and turn on valves near manifold gauge. vacuum for 1 hour.
- turn off valves near manifold gauge for high&low pressure. disconnect vacuum pump.
- connect middle yellow tube to freon bottle. open the bottle valve.
- use screw driver to press the valve in the middle to release air in the yellow tube. usually it’s good to see mist once air is out. if there’s no mist, that’s also ok, just pressure it mulitple times to make sure there’s no air left in the tube.
- turn on the car, turn on MAX AC. open low pressure valve near manifold gauge. low pressure gauge will go up, you will see some liquid in the glass window. make sure it’s not too liquid.
- if AC clutch is not engaging, disconnect the pressure cycle switch near the car battery(use screw driver to push the clipper out, not in, then pull the connector), passenger side. use a short wire to short the connector. (the AC clutch needs to spin for freon to charge). after AC clutch is engage, you should see low pressure gauge drops a little.
- during charging, shake the bottle, warm up the bottle, tilt it, rev up engine to 2000 rpm can help speed up the charging process.
- after finishing one can, turn off low pressure valve, can valve. use another can, use screw driver to pressure valve again to release air. then turn on low pressure valve. never turn on high side valve.
- read the sticker in car to determine how much freon needs to be charged.
- for the last can, use a kitchen scale to calculate how much freon you need to charge. Don’t overcharge the system.
- Notes.
- Using just the simple AC charge tool is not enough to fully charge the AC system.
- the symptom that AC compressor clutch engages once in a while is due to lower pressure of Freon in the system. There’s a pressure cycle switch that monitors the pressure, if pressure is low, it’ll stop the ac compressor to spin; once the pressure is high enough, it’ll spin.
- when the system has no charge at all, need to short the cycle switch to force the AC compressor clutch engage, b/c if clutch doesn’t engage, it will not charge.
- it takes long time (>2hrs) to fully charge. if you see Freon charges slowly, nothing is wrong, just need to be patience and shake the bottles to help accelerate.