A-Premium Universal Coolant Reservoir Tank Bottle 603-001 — Compact 194mm, Vented Cap

A-Premium's Universal Coolant Reservoir Tank Bottle is a non-pressurized overflow and recovery reservoir built from heat-resistant plastic and supplied with a vented twist cap for reliable coolant containment.

This compact, universal overflow bottle (reference 603-001) provides an affordable way to replace a cracked or missing coolant expansion tank. Its lightweight, durable polyamide construction resists engine-bay heat and vibration, and three built-in mounting holes make it straightforward to position in a variety of vehicles and custom installations. The included spring-loaded, vented cap helps manage overflow and evaporation without requiring a pressurized cooling circuit.

How does this reservoir work in a non-pressurized cooling system?

The reservoir serves as a catch and return container for excess coolant as the engine warms and cools. Because it is non-pressurized, it is intended to work with cooling systems that already use a separate pressurized cap or have an open/vented overflow arrangement. The vented cap helps prevent a vacuum during cooldown while allowing excess fluid to escape and return as temperatures change.

• Non-pressurized design suitable for overflow/recovery applications.
• Spring-loaded twist vent cap included to control venting and resealing.
• Clearances sized to accept standard hose connections in many setups.

Will this fit my vehicle or a custom installation?

Built as a universal replacement, this tank is not vehicle-specific but matches many common overflow needs. The three mounting holes let you attach the tank in different orientations, and its compact footprint fits in tight engine bays or behind radiators. Check the listed dimensions against your available space before ordering.

• Reference number: 603-001 (also shown as 603001).
• Dimensions: height 194 mm, length 166 mm, width 105 mm.
• Three mounting holes for flexible positioning and orientation.

What materials and durability can I expect from this tank?

The reservoir is molded from quality engineering plastic chosen for thermal and vibration resistance found in engine compartments. The material minimizes the chance of cracks, swelling, or premature failure under typical automotive conditions. This construction helps maintain coolant containment and reduces the risk of contamination that can affect system performance.

• Constructed from durable polyamide/plastic designed for heat resistance.
• Manufactured under controlled factory conditions for consistent quality.
• Helps protect against oil dilution and related engine contaminants when used properly.

What comes in the box and what warranty covers it?

The package includes the vented, spring-loaded twist cap and the reservoir tank ready for installation. A-Premium backs this product with a one-year unlimited-mileage guarantee, providing added confidence for replacement or retrofit projects. Installation typically requires appropriate hoses and clamps (not included) and basic hand tools.

• Includes: 1 vented twist cap and the universal reservoir tank.
• Pressurized: no; cap pressure rating: not applicable.
• Warranty: A-Premium one-year unlimited-mileage guarantee.

Who is this for: This A-Premium Universal Coolant Reservoir Tank is aimed at DIY mechanics, restoration shops, and vehicle owners needing a dependable overflow bottle for non-pressurized cooling systems or custom installations. Choose this tank when you need a compact, heat-tolerant replacement with flexible mounting options and a factory-backed warranty rather than a model-specific OEM part.