3949850 | York® A/C Compressor With Pulley

Description: An air conditioning (A/C) compressor 3949850 is the heart of a vehicle’s A/C system. It compresses and circulates the refrigerant so the system can remove heat from the inside of the vehicle and release it outside—cooling the cabin. Part Number: 3949850 Condition: New Manufacture/Brand: York Specififcations For 3949850: No. Comp. Cylinders: 2 cyl Comp. Displacement (ci): 10 c.i. Factory Oil Charge: 10 oz oil Fitting Port Position: LH SUCTION Fitting Style: 1”-14 Head Type: TUBE-O Wire Type: None Oil Type: PAG100 Refrigerant Type: R12/R134a Rotation: CW/CCW Shaft Type: Keyed shaft Fits 3949850 For  Freightliner  International / Navistar — older trucks with York style A/C, T/CCI systems Kenworth, Peterbilt, Mack, Volvo, Western Star — many of these use York style compressors Purpose of using 3949850: 1. Compress Refrigerant Gas The compressor takes in low-pressure refrigerant vapor from the evaporator inside the cabin. It compresses it into high-pressure, high-temperature gas. This step is essential because refrigerant must be pressurized to release heat in the condenser. 2. Circulate Refrigerant Through the System The compressor pushes refrigerant through the A/C loop: Evaporator → Compressor → Condenser → Expansion Valve → Back to Evaporator Without the compressor, nothing moves—and the system doesn’t cool. 3. Enable Heat Transfer Once pressurized by the compressor, the hot refrigerant flows to the condenser, where it releases heat to the outside air. Then it cools down, turns into a liquid, and absorbs heat from the cabin air in the evaporator. Signs of a Bad A/C Compressor 3949850:  1. No Cold Air from Vents The most obvious sign. If the compressor isn't working, refrigerant doesn't circulate → no cooling. 2. Compressor Clutch Not Engaging (Applies to belt-driven compressors with a clutch) The clutch allows the compressor to engage or disengage. If it fails: No cold air. Clutch might not spin even when A/C is turned on. You may hear a click (or not) when it tries to engage. 3. Strange Noises Grinding, squealing, knocking, or rattling when A/C is on. Could indicate: Worn bearings Internal damage (pistons, seals) Clutch failure 4. Refrigerant Leaks Look for oil or dye stains around the compressor body or fittings. Leaking refrigerant can lead to: Low system pressure Compressor damage from running dry 5. Circuit Breaker or Fuse Blown Compressor may pull too much electrical current when failing. If the A/C fuse keeps blowing → compressor clutch or coil may be shorted. 6. High Cabin Temperatures Air from vents is warm, even when A/C is on full. Could be: Compressor not working System not building pressure Blockage or restriction due to failed compressor 7. Dashboard Warning Light / A/C Trouble Code Some modern vehicles can detect A/C system faults and trigger: Warning light Diagnostic trouble code (e.g., P0530–P0533 = A/C pressure sensor faults) 8. Visible Damage Cracks or dents in compressor housing Burn marks on clutch Frayed wires About the Manufacturer – York: York-style refers to a specific design of air conditioning compressors originally manufactured by York (now part of T/CCI Manufacturing). These compressors are widely used in heavy-duty vehicles, such as Freightliner, Kenworth, Peterbilt, and International trucks.