A-Premium Radiator Coolant Expansion Reservoir Overflow Tank — GM Trucks/SUVs, 15 PSI Cap & Sensor

The A-Premium Radiator Coolant Expansion Reservoir Overflow Tank is a direct-fit replacement coolant recovery tank with cap and sensor, built for GM trucks and SUVs to restore proper cooling system pressure and fluid level monitoring.

This replacement expansion tank from A-Premium is a complete assembly — reservoir, spring-loaded 15 PSI cap, level/temperature sensor and hose — designed to match factory fit and function on a range of Chevrolet, GMC, Cadillac and Hummer models. Molded from durable PA plastic, it resists heat and vibration and ships with the mounting points and hardware needed for a cleaner, faster swap. Use the Year/Make/Model selector before purchase to confirm compatibility with your vehicle.

Will this reservoir fit my vehicle?

Compatibility covers many GM full‑size trucks and SUVs across late 1990s through mid‑2000s model years. The listing includes exact reference numbers and commonly matched part IDs so you can cross‑check against your vehicle’s original part or service manual.

• Cadillac Escalade 2002–2006
• Chevrolet Avalanche 1500/2500 (2002–2006), Silverado 1500 (1999–2006), Silverado 2500 (1999–2004), Silverado 3500 (2001–2006), Suburban/Tahoe (2000–2006)
• GMC Sierra 1500/2500/3500 and Yukon/Yukon XL 1500/2500 (1999–2006)
• Hummer H2 2003–2009

What are the technical details and what's included?

This unit is a pressurized coolant recovery tank with a spring‑loaded twist cap rated to 15 PSI and a preinstalled sensor for fluid level/temperature signals. It arrives as a ready-to-install kit so you won’t need to salvage parts from the old tank.

• Materials: heat-resistant PA (polyamide) plastic
• Cap: spring-loaded twist, maximum 15 PSI
• Mounting holes: two factory-style locations for straightforward installation
• Box contents: 1 reservoir, 1 cap, 1 sensor, 1 tubing

How does this reservoir help my vehicle's cooling system?

By restoring a sealed expansion volume and proper pressure control, the tank helps maintain coolant level and reduces the risk of air pockets or loss of pressure in the cooling circuit. A correct pressure rating also supports consistent heat transfer and system performance under normal driving conditions.

• Maintains correct system pressure with 15 PSI cap
• Provides accurate coolant level feedback via sensor
• Reduces air intrusion and coolant loss from evaporation or overflow
• Durable PA plastic resists heat and vibration for long service life

Is installation difficult and what should I check after replacing the tank?

Installation is typically straightforward for a home mechanic with basic tools: disconnect the battery, drain or safely work around coolant, unclip lines and electrical connector, remove mounting fasteners and swap components. After installation, refill to the proper coolant level, bleed the system if required and check for leaks while the engine reaches operating temperature.

• Tools: basic hand tools and coolant catch pan
• Procedure: remove old tank, transfer fittings or use supplied parts, reconnect sensor and hose
• Aftercare: refill and bleed cooling system, inspect for leaks and correct sensor operation
• Tip: confirm part numbers (e.g., 603-102, 19353731, GM0713009) before ordering

Who this product is for: The A-Premium Radiator Coolant Expansion Reservoir Overflow Tank is intended for owners and technicians working on compatible Chevrolet, GMC, Cadillac and Hummer models who want a complete, factory-style replacement that includes the cap and sensor. It’s ideal for garages, do-it-yourself mechanics and fleet operators replacing cracked, leaking or non‑functioning reservoir tanks to restore cooling system reliability and instrument readings. A-Premium backs this unit with a one-year unlimited‑mileage guarantee for added confidence in everyday driving use.