Automotive Air Conditioning Information Forum (Archives)

tperk100 on Wed October 19, 2011 3:06 PM

Year: 2004
Make: Ford
Model: F350
Engine Size: 6.0
Refrigerant Type: 134
Ambient Temp: 85
Pressure Low: 0
Pressure High: 0
Country of Origin: United States

04 F350 TD AC stopped cooling.

Compressor engages
Static pressure is ZERO
Running pressures are close to ZERO

Apparently I have lost refrigerant, but I see no signs of leaking (oil) and vacuum is holding at 30.

I am baffled. Any suggestions?

Thanks

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Tom P

tperk100 on Wed October 19, 2011 5:52 PM

I spoke too soon on the vacuum. It would not hold for more than about 30 minutes. I found some oil on the accumulator / evaporator connection. Tightened the connection a little and now vacuum only holds for about 10 minutes!! I suppose I need new seals at this connection.

Daggone it....I anticipate going through a lot of refrigerant to hopefully get this thing going.

After fixing leak, I am really unsure about how much oil remains in the system, whether I should add some, or if the oil included in the 24 oz refrigerant cans will be enough or too much.

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Tom P

mk378 on Wed October 19, 2011 8:01 PM

The connections depend on their o-rings to make a seal, not so much the tightness of the nut. The accumulator-drier should be replaced after having a system leak down to zero. Add about 1 oz of oil to replace that which was in the old drier. Don't use cans of refrigerant with oil or other additives in them, only plain R-134a should be used. You could conduct a static pressure test with a small amount of refrigerant before committing to a full charge, some leaks leak under pressure but not under vacuum.

tperk100 on Thu October 20, 2011 6:30 PM

Mk,

Are you saying that I have not lost any substantial oil with the loss of all refrigerant?

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Tom P

mk378 on Thu October 20, 2011 10:07 PM

Most leaks aren't going to lose much oil, unless it's at the bottom of a part that contains oil. When the refrigerant is not circulating, the oil stays put and only gas leaks out.