Dorman 603-831 Engine Coolant Reservoir - Front

Engine Coolant Reservoir for BMW 528i

This Dorman engine coolant reservoir is a direct replacement for the factory tank on the 2011 BMW 528i, front. Built from plastic to handle underhood heat and engine vibration, it is engineered to match the original fit and function. Part number 603-831 includes the reservoir and cap, along with an integrated level sensor.

Key Features

• Direct replacement engine coolant reservoir for the 2011 BMW 528i, front
• Plastic construction with black finish
• Pressurized design with 20 psi cap rating
• Spring-loaded twist cap included
• Level sensor included
• 1.5 L capacity
• Six mounting holes; irregular shape
• Package contents: 1 coolant reservoir and 1 cap

Detailed Description

Dorman 603-831 is engineered for the BMW 528i cooling system and built to replicate the original reservoir’s fit and function. The pressurized tank uses a spring-loaded twist cap rated to 20 psi and includes a level sensor for factory-style monitoring. With a 1.5 L capacity and six mounting points, this reservoir is made to install in the front position on the 2011 BMW 528i. This part cross-references BMW OE number 17117639021 for the same application.

Common Cooling System Issues

• Cracked or leaking coolant reservoir
• Low coolant level warnings from a failed tank or sensor
• Pressure loss from a worn cap or damaged reservoir neck
• Heat-related plastic fatigue in the original expansion tank
• Coolant odor or visible seepage around the reservoir area

Installation Notes and Tips

Fits 2011 BMW 528i, front. Confirm the reservoir shape, mounting hole count, cap style, and sensor connection before installation. Transfer or connect the level sensor as required by the vehicle configuration, and inspect hoses, clamps, and the cap sealing surface during replacement. Properly bleed the cooling system after installation to help restore normal operation.

Quality Assurance

Dorman manufactures this replacement coolant reservoir from quality materials and designs it to match original part fit and function for the BMW 528i application. Part number 603-831 is built for use in the engine cooling system where heat and vibration resistance matter.