Dorman 603-5203 Heavy Duty Pressurized Coolant Reservoir for Freightliner

The Dorman 603-5203 is a heavy duty pressurized coolant reservoir (degas bottle / coolant recovery tank) engineered as a direct OE replacement for select Freightliner commercial trucks. Manufactured from durable plastic, this reservoir is built to handle the demands of underhood heat and constant engine vibration found in heavy-duty trucking applications.

This reservoir ships as a complete kit and includes two caps and two coolant level sensors, making it a comprehensive replacement solution. The clear construction allows for quick visual inspection of coolant levels without removing the cap. The spring-loaded twist cap is rated to 15 PSI, ensuring a secure, pressurized seal critical to proper cooling system operation.

Key Features:

• Direct OE Replacement – matches the fit and function of the original Freightliner coolant reservoir
• Pressurized Design – 15 PSI spring-loaded twist cap for reliable cooling system pressure maintenance
• Clear Reservoir Body – allows easy visual coolant level inspection without opening the system
• Coolant Level Sensor Included – complete kit includes 2 caps and 2 sensors for a full replacement
• 4 Mounting Holes – drop-in installation with no additional brackets required
• Durable Plastic Construction – engineered to resist underhood heat and engine vibration
• Backed by 100+ Years of Aftermarket Experience – Dorman HD Solutions quality assurance

OEM Cross-Reference Part Numbers: Freightliner A05-33118-000, A05-25263-005, A05-25263-006, A05-25263-007

This heavy duty coolant reservoir is also sold under the Dorman HD Solutions brand and is a trusted aftermarket alternative to OEM Freightliner parts, offering significant cost savings over dealer pricing.