Dorman 603-994 Engine Coolant Reservoir Overflow Tank

The Dorman 603-994 is a direct-replacement engine coolant reservoir, also known as a coolant overflow tank or coolant recovery bottle, designed to match the fit and function of the original factory part. When the OEM reservoir cracks, leaks, or fails, this Dorman replacement restores proper coolant system operation without modification.

Dorman engineers this reservoir to withstand the demanding underhood environment, including exposure to extreme temperature fluctuations, engine vibration, and contact with engine coolant and antifreeze. The durable plastic construction resists expansion, cracking, and degradation over time.

Key Features:

• Direct OEM replacement — matches original part fit and function for a seamless installation
• Durable plastic construction engineered to resist underhood heat, vibration, and coolant exposure
• Helps prevent coolant loss and protects the engine compartment from overflow contamination
• Designed and validated by Dorman's U.S.-based product engineering team
• Backed by over 100 years of automotive aftermarket experience

Dorman's 603-series coolant reservoirs are a trusted solution for repair professionals and vehicle owners looking for a reliable, cost-effective alternative to dealer-sourced OEM parts. This reservoir is sold as an individual unit.