A-Premium Engine Radiator Coolant Expansion Reservoir for Ford Transit 2015–2019 — 21 PSI Cap, Direct-Fit

A-Premium's pressurized coolant expansion reservoir with cap is a direct-fit replacement tank for Ford Transit 150/250/350 (2015–2019) that restores proper coolant overflow capacity and system pressure.

This replacement overflow tank is designed to match factory fit and function for Transit models with 3.2L, 3.5L, and 3.7L engines. Constructed from durable plastic and supplied with a spring-loaded twist cap rated to 21 PSI, the A-Premium unit helps the cooling system maintain correct pressure, store excess coolant, and allow controlled return to the radiator as the engine cools. It ships with the tank and cap and uses the same mounting pattern as the OE assembly for straightforward installation.

Will this reservoir fit my Ford Transit?

Yes — this A-Premium reservoir is made to fit 2015–2019 Ford Transit 150, 250, 350, and 350 HD models with the listed engine sizes. It corresponds to several OEM reference numbers so you can cross-check compatibility before ordering.

• Compatible with Transit-150/250/350/350 HD (2015–2019) 3.2L, 3.5L, 3.7L
• Cross-references: 603-844, 671-00361, BK2Z8A080B, DG9Z8100A
• Confirm Year/Make/Model selection on the product page prior to purchase

How is this expansion tank built and what does the cap do?

The tank is molded from heat- and vibration-resistant plastic engineered for under-hood conditions. The included cap is spring-loaded and rated to a maximum of 21 PSI, which helps preserve proper coolant pressure and controlled overflow behavior under thermal load.

• Material: durable automotive-grade plastic for heat resistance
• Cap: spring-loaded twist design, 21 PSI maximum pressure rating
• Mounting: two mounting holes matching factory locations for secure fit

What practical benefits will I notice after installing it?

Replacing a cracked or leaking reservoir restores the system’s ability to contain and recycle coolant, reducing the risk of air entering the cooling loop and helping the heater core and engine reach intended operating conditions. While it’s not a performance upgrade, a proper reservoir aids consistent cooling system function.

• Restores proper coolant containment and overflow control
• Helps maintain system pressure for reliable heating and cooling
• Reduces risk of coolant loss and air pockets in the system

Is installation difficult and what comes in the box?

Installation is straightforward for anyone comfortable with basic vehicle maintenance; the tank uses the factory mounting points and attaches to existing hoses. The package includes the reservoir and the pressure cap, so you receive the main components needed for a direct swap.

• Contents: 1x reservoir tank, 1x pressurized cap
• Mounting: two factory-style holes, direct-fit replacement
• Recommendation: inspect hoses and clamps during replacement and tighten cap to spec

Who is this for: This A-Premium coolant expansion reservoir is intended for Ford Transit owners and technicians replacing a worn, cracked, or leaking overflow tank on 2015–2019 Transit-150/250/350/350 HD models with 3.2L–3.7L engines. It’s suited to anyone seeking a direct-fit aftermarket replacement with a factory-style cap and clear OEM cross-reference compatibility, including fleets, repair shops, and do-it-yourself mechanics who want a durable, pressure-rated unit backed by a one-year unlimited-mileage guarantee.