Four Seasons 78377 A/C Compressor

Four Seasons 78377 A/C Compressor

The Four Seasons New Compressor 78377 is a new A/C compressor for R134a systems with PAG 46 oil included and a clutch already installed. Built in the Nippondenso 10S20F configuration, it is a direct replacement option for a wide range of Chevrolet Express, GMC Savana, Silverado, Sierra, Yukon, and related applications.

Four Seasons New Compressor line parts are built as new replacement components for service work where the original compressor has failed, lost efficiency, or contaminated the system. This unit is configured for 12-volt operation, serpentine belt drive, tangent mount installation, and sealing-washer suction and discharge ports.

Key Features

• Part number 78377 from Four Seasons New Compressor
• New A/C compressor with clutch included
• R134a refrigerant system application
• PAG 46 oil filled and ready for service
• Nippondenso type 10S20F compressor design
• 12-volt coil with pin terminal connection
• Serpentine belt pulley with 4-groove design
• Sealing-washer suction and discharge ports
• Tangent mount style for confirmed vehicle applications

Detailed Description

Four Seasons 78377 is engineered for vehicles using the Nippondenso 10S20F compressor platform and is listed across many GM truck and van applications, including Chevrolet Express 2500 and Express 3500, GMC Savana 2500 and Savana 3500, Chevrolet Silverado and GMC Sierra models, plus Cadillac Escalade and GMC Yukon platforms in specific configurations. It is also cross-referenced to Monroe Shocks & Struts 272531 for the same application.

This compressor includes the clutch and comes oil filled with PAG 46, which supports service replacement on R134a systems. The pulley uses a 4-groove serpentine belt setup, and the unit uses sealing washers at both suction and discharge ports. Fitment notes on several applications call for the OE manifold, a stretch-fit belt replacement, or a DeSlugger to reduce compressor damage on low-mount compressor vehicles.

What This Compressor Helps Address

• Loss of cabin cooling from a worn or seized compressor
• Noisy compressor operation or clutch-related A/C failure
• Refrigerant circulation problems in R134a systems
• Service replacement after internal compressor contamination
• Restoration of A/C function on GM vans and trucks with 10S20F applications

Installation Notes and Tips

• Verify the vehicle uses the 10S20F compressor configuration before ordering.
• Review OE manifold requirements on listed applications before installation.
• Replace the stretch-fit belt where the fitment notes specify it.
• Follow the vehicle-specific oil and refrigerant service procedure for R134a systems.
• Use the recommended DeSlugger on low-mount compressor vehicles noted in the fitment data.

Quality Assurance

Four Seasons supplies this compressor as a new replacement part with application-specific fitment data for GM vans, trucks, and SUVs. Part number 78377 is cataloged for direct service use in confirmed applications and is supported by detailed OE-style mounting and port specifications.