Four Seasons 38637 A/C Expansion Valve - Front

Four Seasons 38637 Expansion Valve Overview

The Four Seasons 38637 expansion valve is a brass TXV built for R134A air conditioning systems that need precise refrigerant metering and stable evaporator control. With an 8.0 super heat setting, it supports consistent A/C performance in a wide range of Nissan, INFINITI, Isuzu, Honda, and Subaru applications.

As part of the Four Seasons Expansion Valve line, this component is focused on accurate refrigerant flow control for service and replacement work on factory-style HVAC systems. The Four Seasons 38637 is a direct-fit style A/C expansion valve for many older import platforms, including Nissan Maxima, Nissan Pathfinder, and INFINITI I30 applications.

Key Features

• Brass construction for A/C system service applications
• TXV design for controlled refrigerant metering
• Configured for R134A refrigerant systems
• 8.0 super heat specification
• Part number 38637 for catalog and service reference
• Cross-reference part number: Dorman - HELP 91100

Detailed Description

The Four Seasons Expansion Valve 38637 regulates refrigerant flow into the evaporator so the HVAC system can maintain proper cooling balance. This TXV-style valve is used in R134A-equipped systems where accurate super heat control is important for compressor protection and cabin cooling consistency. It is listed across a broad range of import vehicles, including Fits 1991-1999 Nissan Maxima, N/A; Fits 1987-1995 Nissan Pathfinder, N/A; and Fits 1996-1999 INFINITI I30, N/A.

Additional fitment coverage includes Nissan 240SX, 300ZX, D21, Sentra, 200SX, and 720, along with Isuzu Rodeo, Trooper, Amigo, Honda Passport, Subaru Legacy, and select INFINITI and Nissan models. If you are searching for a Four Seasons 38637 expansion valve for Nissan Maxima or a TXV replacement for older Nissan and INFINITI A/C systems, this part number is a relevant service match.

Common A/C Problems This Valve Can Address

• Weak or inconsistent cabin cooling
• Improper refrigerant metering at the evaporator
• Compressor cycling caused by flow control issues
• High or unstable evaporator super heat readings
• Service replacement for worn or restricted expansion valves

Installation Notes and Tips

Verify refrigerant type, system configuration, and OE part number before installation. Clean the A/C lines and inspect seals, O-rings, and mating surfaces during service to help prevent leaks. Because fitment varies by year, make, and model, confirm the vehicle listing carefully before ordering the Four Seasons 38637.

Quality Assurance

Four Seasons supplies HVAC service parts for automotive A/C repair, and this expansion valve is cataloged with defined refrigerant and super heat specifications to support accurate replacement selection. Use the listed fitment data and interchange references when matching the valve to the vehicle application.