Automotive Air Conditioning Information Forum (Archives)

torque395 on Sun July 31, 2011 2:03 PM

Year: 1996
Make: Chevy
Model: Suburban
Engine Size: 6.5L
Refrigerant Type: R134A
Ambient Temp: 90
Country of Origin: United States

i'm trying to blow oil out of my system and cant blow backwards through the evaporator. I can blow forwards but not backwards. Does the orifice tube keep the flow from going backwards?

Also when blowing forwards, stuff that looks like smoke comes out of the evaporator. Smoke or steam looking stuff and it smells like refrigerant. What is it really? Oil boiling off?

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

Dougflas on Sun July 31, 2011 2:36 PM

you have to remove the metering device (Orfice tube)

torque395 on Sun July 31, 2011 3:04 PM

ok thanks What was the smokey looking stuff coming out?

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

Edited: Sun July 31, 2011 at 3:05 PM by torque395

mk378 on Sun July 31, 2011 6:34 PM

Oil mist. Or water if you're not using dry air.

torque395 on Sun July 31, 2011 11:24 PM

Must have been oil mist. I'm not using a dryer, but the air coming out of my blow gun is not blowing moisture. Visible anyways.

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1996 Chevy Suburban 2500 4x2 6.5L Turbo

TRB on Sun July 31, 2011 11:27 PM

Oil vapor or the moisture from the compressed air would be my guess.

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mk378 on Sun July 31, 2011 11:30 PM

As you cool the air (since an evaporator is designed to be a heat exchanger), the moisture will condense out. You need to use very dry air or nitrogen, etc (NOT oxygen) from a tank to get it dry inside.