Compressor HVAC: Description and Operation

The FS-10 is a swash plate design 10-cylinder aluminum compressor using the tangential design mount. The A/C compressor main shaft is driven by an accessory drive belt from the engine crankshaft pulley. A one-piece lip-type seal (replaceable from the front of the A/C compressor) seals the A/C compressor at the shaft opening. Five double-acting pistons, positioned axially around the A/C compressor shaft, operate within the cylinder assembly. The pistons are actuated by a swash plate that is pressed on the A/C compressor shaft. The swash plate changes the rotating action of the shaft to provide a reciprocating driving force to each of the five pistons. This driving force is applied, through shoes, to the midpoint of each of the double end pistons.

NOTE: Internal A/C compressor components are not serviced separately. The FS-10 A/C compressor is serviced only as an assembly. The A/C clutch, A/C clutch pulley, and the shaft seal are serviceable.

Reed-type suction and discharge valves are assembled on the valve plate, which are located between the cylinder assembly and the head at each end of the A/C compressor. Gas-tight passageways between the heads direct the refrigerant gas to the suction and discharge ports located in the A/C compressor head.

An A/C clutch drives the A/C compressor shaft. When voltage is applied to the A/C clutch, the clutch plate and hub assembly (which is connected to the A/C compressor shaft) is drawn rearward by magnetic force toward the A/C clutch pulley, which rotates freely on the A/C compressor front head casting. The magnetic force locks the clutch plate and hub assembly and the A/C clutch pulley together as one unit. The A/C compressor shaft then turns with the A/C clutch pulley. When voltage is removed from the A/C clutch field coil, springs in the A/C clutch move the clutch plate away from the A/C clutch pulley and the A/C compressor shaft stops rotating.


An A/C compressor serves two primary functions. First, it pumps refrigerant type R-134a and refrigerant oil throughout the A/C system. Second, it compresses low-pressure R-134a vapor as it pumps, greatly increasing the pressure and temperature of the R-134a. The A/C compressor is driven by the crankshaft pulley via an A/C compressor drive belt. The A/C compressor circuit is completed when the climate control assembly A/C switch is pressed. Assuming all A/C system components are operating normally, the Powertrain Control Module (PCM) then energizes the compressor via the A/C clutch.

The FS-10 type A/C compressor is used in this vehicle. It is a Ford built A/C compressor with a displacement of 170 cc (10.40 cu. in.), and is lubricated with a charge of Motorcraft YN-12b or equivalent refrigerant oil, meeting Ford specification WSH-M1C231-B. The evaporator to compressor suction line includes the suction and discharge manifold which is mounted on the rear face of the A/C compressor and is secured with a single bolt. A system pressure relief valve is located in the discharge line.