Four Seasons 3645NK A/C Compressor Kit - Front

Complete A/C Kit for Trailblazer and Envoy

Restore front air conditioning performance with the Four Seasons Complete A/C Kit 3645NK. This kit combines a new compressor with the matching accumulator, orifice tube, oil, and O-rings for a service package built around R134A systems.

Compatible with 2003-2009 Chevrolet Trailblazer, front, and related applications including GMC Envoy, Saab 9-7x, Isuzu Ascender, Trailblazer EXT, Envoy XL, and Envoy XUV, this Four Seasons 3645NK kit is organized for direct system service on the listed vehicles.

Key Features

• Complete A/C compressor kit with new compressor
• Uses R134A refrigerant
• PAG 46 oil included for R134A systems
• Includes accumulator, orifice tube, oil, and O-rings
• 6-groove pulley design with 3.875 in. outside pulley diameter
• Orifice tube style: standard, yellow/white
• Accumulator uses P-nut inlet and outlet fittings
• Limited lifetime warranty

Product Details

The Four Seasons Complete A/C Kit line is built for full-system repair rather than a compressor-only replacement. Part number 3645NK includes the compressor, accumulator, orifice tube, and specified PAG 46 oil so the major wear items in the front HVAC circuit can be serviced together. Four Seasons states its mobile A/C products are engineered and tested for long service life, drawing on more than 50 years of HVAC experience. This kit is a direct-fit solution for 2003-2009 Chevrolet Trailblazer, 2003-2009 GMC Envoy, 2005-2009 Saab 9-7x, and other listed front A/C applications.

This part cross-references Four Seasons 3645NK for the same application.

What It Helps Fix

• Weak or inconsistent front cabin cooling
• Noisy or failing A/C compressor operation
• Restricted refrigerant flow at the orifice tube
• Moisture or contamination concerns in the A/C circuit
• Loss of system efficiency after compressor service

Installation Notes and Tips

Before installation, verify the vehicle uses R134A refrigerant and the listed front application. Replace the accumulator and orifice tube during compressor service, and flush the system as needed to remove debris from the previous failure. Confirm pulley groove count, fitting style, and oil type before charging the system. Always follow the vehicle service procedure for evacuation, leak checking, and refrigerant charge.

Quality Assurance

Four Seasons backs this kit with a limited lifetime warranty. The brand positions its HVAC components around tested performance and long-term reliability for mobile air conditioning repair.