Dorman 603-755 Engine Coolant Reservoir - Front

Overview of Dorman Engine Coolant Reservoir 603-755

The Dorman 603-755 engine coolant reservoir is designed for select BMW models, including the 135i, 135is, 335i, 335i xDrive, M135i, and X1. This pressurized coolant reservoir is made from durable plastic and includes a spring loaded twist cap and level sensor to maintain optimal engine cooling system performance.

• Material: Durable plastic construction
• Capacity: 1.6 liters
• Color: Black
• Dimensions: 8.75 inches length, 9.75 inches height
• Pressurized reservoir with 20.3 psi maximum cap pressure rating
• Includes spring loaded twist cap and level sensor
• Mounting holes: 2 (mounting hardware and brackets not included)
• Shape: Irregular to fit specific engine bay configurations

Detailed Product Description

The Dorman 603-755 engine coolant reservoir is engineered to meet the cooling system requirements of various BMW vehicles such as the 135i, 135is, 335i, 335i xDrive, M135i, and X1. Constructed from high-quality plastic, this reservoir is designed to withstand the pressures of a pressurized cooling system, with a cap rated for up to 20.3 psi. The included spring loaded twist cap ensures a secure seal, while the integrated level sensor provides accurate coolant level monitoring to prevent overheating and maintain engine efficiency. Its irregular shape and two mounting holes allow for proper fitment within the engine compartment, although mounting hardware and brackets are not included.

Compatible Vehicles and Common Applications

• Replacement for faulty or cracked coolant reservoirs in BMW 135i and 135is models
• Restores proper coolant level monitoring in BMW 335i and 335i xDrive vehicles
• Used to maintain cooling system integrity in BMW M135i and X1 models
• Addresses coolant leaks and pressure loss issues
• Helps prevent engine overheating caused by reservoir damage or sensor failure

Installation Notes and Tips

When installing the Dorman 603-755 engine coolant reservoir, ensure the vehicle is cool and the engine is off. Carefully remove the old reservoir and disconnect the level sensor wiring. Align the new reservoir using the two mounting holes, securing it with appropriate hardware (not included). Connect the level sensor and verify proper electrical connections. Fill the reservoir with the recommended coolant type and check for leaks. After installation, monitor coolant levels and system pressure to confirm correct operation.

Quality Assurance and Warranty

Dorman parts are manufactured to meet or exceed OEM specifications for fit, form, and function. The 603-755 engine coolant reservoir undergoes rigorous quality control to ensure durability and reliability in demanding automotive environments. This part includes a limited warranty covering defects in material and workmanship, providing confidence in its long-term performance for your BMW 135i, 135is, 335i, 335i xDrive, M135i, or X1 vehicle.