603-839 Engine Coolant Reservoir w/Cap For 2013-2018 Ram 2500 3500 4500 5500

Engine Coolant Reservoir with Cap for Ram 2500, 3500, 4500, 5500 (2013-2018)

This engine coolant reservoir with cap replaces the factory tank on 2013-2018 Ram 2500, 3500, 4500, and 5500 trucks, cross-referencing OEM part number 603-839.

Overview

This engine coolant reservoir with cap serves as a direct replacement for the coolant expansion tank on 2013-2018 Ram 2500, 3500, 4500, and 5500 diesel trucks. It holds excess coolant as the engine heats up and returns it when cooling, helping maintain proper system pressure and level. Fleet managers and individual owners choose this engine coolant reservoir for its exact fit and durable construction.

Built For Performance

• Manufactured from high-strength, heat-resistant plastic
• Includes a pressure-rated cap to maintain system integrity
• Molded-in fluid level markings for quick visual checks
• Precise OEM-style dimensions ensure straightforward bolt-in installation
• Reinforced mounting points resist stress cracking
• Translucent tank allows coolant level inspection without opening

Fits These Machines

• for Ram 2500 (2013-2018)
• for Ram 3500 (2013-2018)
• for Ram 4500 (2013-2018)
• for Ram 5500 (2013-2018)

On-The-Job Use

• Restoring coolant system function in daily-driven Ram pickups
• Replacing cracked or leaking reservoirs on construction fleet trucks
• Upgrading aged tanks during cooling system overhauls
• Maintaining consistent coolant levels under heavy towing conditions
• Simplifying routine level checks at service intervals

Specs At A Glance

Good To Know

Q: Will this coolant reservoir fit both diesel and gas Ram models? A: It is specifically designed for the diesel engines in 2013-2018 Ram 2500–5500 trucks; confirm your engine type before ordering.

Q: How can I tell if my original reservoir is failing? A: Common signs include visible cracks near the seams, coolant residue around the tank, or a drop in coolant level without an external leak.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.