Dorman 902-5003 Engine Coolant Thermostat Housing - Engine Block

Overview of Dorman Engine Coolant Thermostat Housing

The Dorman 902-5003 engine coolant thermostat housing is designed for reliable cooling system performance in select BMW models. Constructed from durable black plastic, this thermostat housing includes a gasket for a secure seal and is engineered to meet OEM specifications.

• Material: High-quality black plastic for corrosion resistance
• Includes gasket for proper sealing
• Outlet port diameter: 1.5 inches
• Four mounting holes with 0.313 inch diameter each
• Compatible with multiple BMW models including 320i, 325i, M3, and Z3
• Thermostat not included
• No bolts or air vent (bleeder valve) included

Detailed Product Description

The Dorman 902-5003 thermostat housing is a direct replacement part designed specifically for BMW vehicles such as the 320i, 323i, 325i, 328i, 525i, M3, and Z3 models. Made from durable plastic, it offers resistance to corrosion and heat, ensuring long-lasting performance within the engine cooling system. The housing features a 1.5-inch outlet port diameter and four mounting holes sized at 0.313 inches, providing a secure and precise fit. This part comes with a gasket included to ensure a tight seal and prevent coolant leaks. Note that the thermostat itself is not included, and no bolts are provided with this housing.

Compatible BMW Models and Applications

• BMW 320i, 323i, 323is, 323ti
• BMW 325i, 325is, 328i, 328is
• BMW 525i, 525iT
• BMW M3
• BMW Z3

Common Issues Addressed by This Thermostat Housing

• Coolant leaks caused by cracked or damaged thermostat housing
• Overheating due to improper coolant flow
• Corrosion-related failures in original housing components
• Loose or damaged mounting points affecting seal integrity
• Replacement of worn or brittle plastic housings

Installation Notes and Tips

• Ensure the engine is cool before beginning installation to avoid burns
• Use the included gasket to prevent coolant leaks and ensure a proper seal
• Check mounting holes and hardware compatibility; bolts are not included
• Inspect the thermostat separately as it is not included with this housing
• Torque mounting bolts to manufacturer specifications to avoid damage

Quality Assurance and Warranty

Dorman parts are manufactured to meet or exceed OEM standards for fit, form, and function. The 902-5003 thermostat housing undergoes rigorous quality control to ensure durability and reliable performance in BMW cooling systems. While specific warranty details may vary, Dorman typically offers limited warranties covering defects in material and workmanship.