Automotive Air Conditioning Information Forum (Archives)

vicster on Thu June 25, 2015 9:01 PM

Year: 2003
Make: Ford
Model: F250 Super Duty KR
Engine Size: 6.0
Refrigerant Type: 134A
Ambient Temp: 80
Pressure Low: 25
Pressure High: 145
Country of Origin: United States

2003 F250 KR 6.0, 200,000miles. AC started cycling last year no real pattern would just start blowing warm, may start up again may not. Gauges at 80 ambient temp, low side 25, high side 145 (which is way low). Evacuated system changed orifice tube, about one third blocked few shavings nothing really bad. Recharged, 2 lbs 10 oz, made adjustments for hose loss. Cooling temp inside between 44 and 50. Still cycling, pressure switch is kicking system off as required around 25 psi, high side still only 150psi.

Checked air gap in compressor, good. Jumped switch compressor stayed on.

When I pulled vacuum last night let it sit overnight no loss.

Checked temps at accumulator about 47 going in about 59 coming out, it actually froze up yesterday.

I am thinking accumulator is clogged, starving compressor.............

Dougflas on Thu June 25, 2015 9:09 PM

Fords back then had bad cycling switches.

vicster on Thu June 25, 2015 10:02 PM

Low pressure switch?

bad switch would explain low high pressure?

bohica2xo on Fri June 26, 2015 2:58 AM

I have had a Ford cycling switch do some crazy stuff. Cycle off @ 28psi, then back on @ 80 psi, then off @ 42 psi... Replace it if it is original

As for the high side, does it change when the compressor cycles? If it does not move, your service coupler may not be depressing the schrader valve properly.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

vicster on Fri June 26, 2015 6:09 AM

Yes high side is moving, just wont go above 148. Hooked up to second vehicle gauges working properly. I assume you do not suspect a restricted accumulator?

bohica2xo on Sun June 28, 2015 2:33 AM

An accumulator blockage would cause high pressures on the low side.

The 145 psi is suspiciously close to underhood static pressure on an 85f day. If that pressure is indeed accurate, the discharge line from the compressor should be barely warm.

If the discharge is just warm, then the compressor may be tired. What sort of pressures do you get at full load? That would be with the cabin fan on highest speed, doors open & engine rpm above 1500 rpm.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

vicster on Sun June 28, 2015 6:46 AM

Thanks, well it was not the accumulator, ordering new compressor and condenser.

Dougflas on Sun June 28, 2015 9:53 AM

you should also order a new accumulator. And why not change the cycling switch while you're there?

vicster on Sun June 28, 2015 11:50 AM

Yep you are correct, I also ordered a new condenser mine is fairly beat up. New components should help. Thanks for the suggestions. Total cost in parts will be 210.00 delivered, not bad.

vicster on Sun July 12, 2015 7:33 AM

After replacement of compressor, condenser, orifice tube, accumulator and flush, evac and charge the system is operating very well.

Jag987 on Sun July 12, 2015 5:27 PM

210 for all those parts?

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

vicster on Sun July 12, 2015 5:51 PM

Condenser 55.00 RockAuto
Compressor 104.00 EBAY R&Y A/C Compressors
Accumulator 35.99 Orielly Auto Parts