GDUKOP engine coolant overflow reservoir tank 603-955 — direct-fit PP bottle with hoses for Buick/Chevrolet

GDUKOP 603-955 engine coolant overflow reservoir tank is a direct-replacement coolant expansion tank kit designed to restore proper coolant storage and pressure control for compatible Buick, Chevrolet Tracker and Trax models.

This replacement radiator overflow bottle is molded from durable polypropylene to withstand engine heat, vibration and everyday under-hood exposure. The kit includes the reservoir tank, an air bleed hose and a premium molded heater hose for a straightforward swap that matches OE fitment numbers 603-955, 95269001, 95201979 and 95380033. It is engineered to be a hassle-free direct fit for many 2013–2021 small SUVs and compact crossovers so you can maintain correct coolant levels without costly dealer parts.

Which cars is this reservoir tank compatible with?

This GDUKOP tank is built as a direct replacement for several GM small crossover models. Confirm fitment by matching your vehicle year, engine and the listed OE numbers before purchasing.

• 2013–2021 Buick Encore with 1.4L L4 engine
• 2013–2014 Chevrolet Tracker with 1.8L L4 engine; 2015 Tracker with 1.4L L4
• 2013–2019 Chevrolet Trax with 1.8L L4; 2013–2021 Trax with 1.4L L4
• Replacement OE numbers: 603-955, 603955, 95269001, 95201979, 95380033

How does this replacement tank improve my cooling system performance?

By replacing a cracked, warped or leaking overflow bottle you restore the cooling system's ability to capture expanding coolant and return it as the engine cools. That helps keep coolant levels stable and reduces the risk of air entering the cooling loop, which can cause hot spots and reduced heater performance.

• Correctly stores excess coolant during high engine load and returns it as temperatures normalize
• Resists heat and vibration to minimize leaks and deformation
• Includes bleed hose to purge trapped air for consistent cooling operation

What materials and parts are included in the kit?

The reservoir is constructed from high-quality polypropylene (PP) designed for longevity in under-hood conditions. The kit provides everything needed for a typical replacement so you won’t have to hunt for hard-to-find hoses or fittings.

• 1 x GDUKOP engine coolant reservoir tank (PP plastic)
• 1 x coolant reservoir air bleed hose for removing trapped air
• 1 x premium molded heater hose for direct replacement
• Compatible cap included to maintain correct system pressure

How difficult is installation, and what should I check after fitting?

Installation is straightforward for anyone comfortable with basic DIY auto work; the part is designed for direct fit where mounting points and hose connections line up with OEM locations. After installation, top up to the recommended coolant level, run the engine to operating temperature, and inspect for leaks and proper bleed.

• Remove old reservoir, swap hoses and secure mounting points
• Refill coolant to the indicated level and bleed system using included hose
• Inspect for leaks after a warm-up cycle and recheck fluid level

Who is this for? The GDUKOP 603-955 coolant overflow reservoir tank is intended for owners and technicians servicing 2013–2021 Buick Encore, 2013–2019/2021 Chevrolet Trax, and 2013–2015 Chevrolet Tracker models who need an affordable, OE-referenced replacement. It’s especially useful for drivers experiencing visible coolant loss, cracked or discolored tanks, or air-trapping symptoms in the cooling system and for DIY mechanics seeking a reliable, direct-fit replacement with the hoses included.