A-Premium Coolant Expansion Tank for Chevrolet, GMC & Cadillac — With Cap, Direct-Fit PA Plastic

A-Premium Engine Radiator Coolant Expansion Reservoir Overflow Tank with Cap is a direct-fit plastic coolant expansion tank engineered to replace the factory overflow reservoir on compatible Chevrolet, GMC and Cadillac trucks and SUVs.

This replacement reservoir tank arrives ready to install and includes the pressure cap. Molded from heat- and vibration-resistant polyamide (PA) plastic, it is offered in the factory-style white and black finish and matches the original mounting points and hose connections for a direct-replacement fit. The part is sold with reference numbers 15650373 and 603-100 and lists broad vehicle compatibility across late‑1980s through early‑2000s Chevrolet, GMC and Cadillac heavy-duty and full-size models—confirm year/make/model before purchase.

Which vehicles will this expansion tank fit?

This A-Premium tank is designed to replace the factory reservoir on many Chevrolet, GMC and Cadillac models across multiple years. Fitment covers a wide range of light and heavy-duty trucks and SUVs, but compatibility varies by specific model and production year.

• Chevrolet: Blazer (1992–1994), C/K 1500 (1988–1999), Suburban and Silverado heavy-duty ranges.
• GMC: C/K 1500, C2500/C3500 series, Yukon (1992–2000) and various Suburban configurations.
• Cadillac: Escalade (1999–2000) and other select GM platforms using the same reservoir design.

How does this tank hold up to heat and vibration?

Constructed from reinforced polyamide (PA) plastic, the tank withstands typical under-hood temperatures and the vibration found in heavy-duty applications. That material choice reduces the likelihood of cracks, swelling or pressure-related failure compared with lower-grade polymers.

• PA plastic resists high temperatures and maintains dimensional stability.
• Factory-style welds and mounting points keep the tank secure under vibration.
• Includes the pressure cap to restore the proper coolant system seal and recovery function.

What practical benefits will I notice after replacing the reservoir?

Replacing a cracked or leaking expansion tank restores coolant containment and recovery, which helps maintain proper coolant level and system pressure. That stability supports consistent engine cooling and can prevent overheating events related to coolant loss.

• Eliminates visible leaks and coolant puddles beneath the vehicle.
• Restores proper expansion and recovery cycles during heat soak and cool-down.
• Helps protect the heater core and engine components from coolant loss consequences.

Is installation straightforward or do I need professional service?

Installation is typically straightforward for anyone comfortable with basic automotive maintenance. The tank uses original mounting points and hose connections, so removal of the old reservoir and bolting in the new unit is usually a simple swap; just drain and capture coolant, disconnect hoses, and reinstall.

• Direct-replacement fitment reduces modification or fabrication needs.
• Basic tools required: pliers, screwdrivers, and possibly a socket set.
• Refill coolant and burp the system after installation to remove air pockets.

Who is this for: This A-Premium expansion reservoir is aimed at owners and technicians of compatible Chevrolet, GMC and Cadillac full-size trucks and SUVs who need a cost-effective, OEM-style replacement. It suits people replacing brittle or leaking tanks, restoring system integrity after collision damage, or performing preventative maintenance on older vehicles. The product is backed by a one-year unlimited-mileage guarantee from A-Premium for added confidence, but always verify part numbers and vehicle year/model before ordering to ensure proper fitment.