Dorman 902-5123XD Engine Coolant Thermostat Housing Assembly

OE Fix Thermostat Housing for Toyota and Lexus

Dorman 902-5123XD is an engine coolant thermostat housing assembly built for select Toyota and Lexus applications that use a plastic water outlet prone to warping from repeated heat cycling. This aluminum replacement includes the thermostat and gasket for a complete repair, helping restore proper coolant flow in one service.

Compatible With 2004-2006 Lexus RX330 and 2004-2006 Toyota Sienna applications, including the 2004-2006 Toyota Sienna thermostat housing assembly with thermostat included. The Dorman 902-5123XD is a direct-fit cooling system repair part for drivers replacing a failed OE plastic housing.

Key Features

• Aluminum housing construction for improved durability over the original plastic outlet
• Includes thermostat and gasket for a complete thermostat housing repair
• Standard replacement grade for select Toyota and Lexus cooling system applications
• One outlet port and one mounting hole design
• Thermostat opening temperature: 82 Deg. C
• Black and natural finish with aluminum and rubber materials

Detailed Description

This engine coolant thermostat housing assembly addresses a common failure point on select Toyota and Lexus vehicles where the original plastic water outlet can distort and leak after repeated temperature cycling. Dorman 902-5123XD replaces that housing with an aluminum OE FIX design and includes the thermostat and gasket needed to complete the repair. It is a practical choice for a 2004-2006 Lexus RX330 thermostat housing replacement or a 2004-2006 Toyota Sienna coolant outlet repair when the original part has warped, cracked, or begun leaking. This part cross-references Motorad (e.g., 281-180, CH2123) for the same application.

Common Problems This Part Can Address

• Coolant leaks at the thermostat housing
• Warped or cracked plastic water outlet
• Overheating caused by restricted thermostat operation
• Failed gasket or seal at the housing interface
• Repeated thermostat housing replacement on the same vehicle

Installation Notes and Tips

Drain the cooling system before removal, clean the mating surfaces thoroughly, and inspect the hose connection and surrounding coolant passages for residue or damage. Verify the thermostat orientation and gasket placement during installation, then refill and bleed the cooling system according to the vehicle service procedure. Confirm fitment for 2004-2006 Lexus RX330 and 2004-2006 Toyota Sienna before installation.

Quality Assurance

Dorman OE FIX parts are engineered as upgraded replacements for known failure points in original equipment designs. This aluminum thermostat housing assembly is built to replace the factory plastic outlet with a more durable service part for select Toyota and Lexus cooling system repairs.