Dorman 603-125 Engine Coolant Reservoir - Front

Reliable Engine Coolant Reservoir for Chevrolet and GMC Trucks

The Dorman 603-125 engine coolant reservoir is designed to maintain optimal cooling system performance for select Chevrolet and GMC heavy-duty trucks. Constructed from durable plastic with a clear finish, this reservoir allows for easy fluid level monitoring and is engineered to meet the demands of Sierra and Silverado 2500 HD and 3500 models.

• Durable plastic construction with clear color for fluid visibility
• Compatible with Chevrolet and GMC Sierra 2500 HD, Sierra 3500, Silverado 2500 HD, and Silverado 3500 models
• Includes one coolant reservoir and one spring loaded twist cap rated for 15 psi pressure
• Pressurized design supports efficient cooling system operation
• Two mounting holes for secure installation (mounting hardware not included)
• Cap included with spring loaded twist type for reliable sealing
• Dimensions: Length 298 mm, Height 315 mm

Product Details and Specifications

The Dorman 603-125 engine coolant reservoir is made from high-quality plastic, providing resistance to heat and corrosion commonly found in engine compartments. Its clear color allows for quick visual checks of coolant levels without removing the cap. The reservoir is pressurized and comes with a spring loaded twist cap rated for a maximum pressure of 15 psi, ensuring proper system pressure and preventing coolant loss. With two mounting holes, the reservoir can be securely attached to the vehicle, although mounting hardware and brackets are not included. This part is specifically designed for use in Chevrolet and GMC heavy-duty trucks including the Sierra 2500 HD, Sierra 3500, Silverado 2500 HD, and Silverado 3500 models, ensuring proper fit and function.

Common Applications and Problem Resolution

• Replacement for cracked or leaking coolant reservoirs
• Restores proper coolant level monitoring and containment
• Prevents coolant loss due to faulty or damaged reservoir caps
• Helps maintain correct cooling system pressure to avoid overheating
• Addresses coolant contamination from reservoir damage

Installation Notes and Tips

Installation of the Dorman 603-125 engine coolant reservoir requires removal of the old reservoir and securing the new unit using the existing mounting points. Note that mounting hardware and brackets are not included, so retain or replace these as needed. Ensure the spring loaded twist cap is properly seated to maintain system pressure. After installation, refill the cooling system with the appropriate coolant and check for leaks. It is recommended to inspect hoses and connections during installation to ensure overall system integrity.

Quality Assurance and Warranty

Dorman parts are manufactured to meet or exceed OEM standards for fit, form, and function. The 603-125 engine coolant reservoir undergoes quality checks to ensure durability and performance under typical operating conditions. This part includes the coolant reservoir and cap, both designed for reliable service life. Please refer to Dorman's warranty policy for specific coverage details.