Dorman 603-5502 Engine Coolant Reservoir - Front

Engine Coolant Reservoir for OE Fit

Dorman 603-5502 is a replacement engine coolant reservoir built from plastic to handle underhood heat and engine vibration. It is engineered to match the original part’s fit and function, with a pressurized design and a spring-loaded twist cap rated to 10 psi.

For drivers searching for a Dorman coolant reservoir, engine coolant overflow tank, or radiator expansion tank replacement, this part number 603-5502 provides a direct-fit service solution for restoring proper coolant storage and system pressure control.

Key Features

• Plastic reservoir construction for underhood durability
• Pressurized design with 10 psi cap rating
• Spring-loaded twist cap included
• Engineered to match original fit and function
• White housing for easy visual inspection of coolant level
• Cross-reference part numbers include 575.1053 and 25174629

Detailed Description

This Dorman engine coolant reservoir is made to replace a damaged, cracked, or leaking factory tank while maintaining the original mounting and system layout. The pressurized reservoir works with the cooling system to store expanding coolant as engine temperature rises, then return it as the system cools. Part number 603-5502 is a practical choice for a Dorman coolant reservoir replacement when the original tank no longer holds pressure or shows signs of age-related wear.

Vehicle owners searching for a coolant reservoir for Chevrolet Malibu, Pontiac G6, or Saturn Aura applications should verify their exact model year and cooling system configuration before ordering. The reservoir is supplied with a cap and is built to match OE-style fitment for service replacement use.

What It Helps Fix

• Coolant leaks from a cracked reservoir
• Low coolant level caused by tank seepage
• Pressure loss from a worn or damaged cap seal
• Overflow or expansion tank deterioration from heat cycling
• Visible coolant contamination from a failing plastic tank

Installation Notes and Tips

Inspect the mounting area, hoses, and cap sealing surfaces before installation. Transfer any connected hoses carefully and confirm the reservoir seats correctly in the original location. Because mounting hardware is not included, reuse the existing fasteners if serviceable. After installation, fill and bleed the cooling system according to the vehicle service procedure and check for leaks at operating temperature.

Quality Assurance

Dorman manufactures this replacement coolant reservoir from quality materials to withstand heat and vibration in the engine bay. It is engineered to match original part fit and function for dependable service replacement.