Dorman Front Pressurized Coolant Reservoir with Cap for Cadillac Chevy GMC - Direct Replacement, Thermoplastic

Dorman 603-054 is a direct-replacement front pressurized engine coolant reservoir with cap engineered to restore proper coolant containment and fit the original mounting and hose connections on compatible Cadillac, Chevrolet and GMC models.

This replacement coolant overflow bottle is manufactured from durable thermoplastic and supplied with a preinstalled cap so you can quickly return a vehicle’s cooling system to service. It’s built to match the form, mounting points and hose ports of the factory part so installation is straightforward for DIYers or professional technicians. Before ordering, confirm vehicle compatibility using your trim and year in the garage tool to ensure the Confirmed Fit indicator applies to your specific model.

What vehicles does this reservoir fit?

The Dorman 603-054 reservoir is made for a range of late-2000s and 2010s Cadillac, Chevrolet and GMC full-size SUVs and trucks, including Escalade, Silverado, Sierra, Tahoe, Suburban, Yukon and Avalanche models. Fitment covers multiple model years and variants—see the garage tool for exact matching by trim.

• Compatible with Cadillac Escalade, Escalade ESV and Escalade EXT years listed in the fitment tool.
• Fits Chevrolet Silverado 1500/2500/3500, Tahoe, Suburban, Avalanche and Cheyenne across specified years.
• Compatible with GMC Sierra 1500/2500HD/3500HD and Yukon/Yukon XL models in the listed years.
• Always verify fit using the Confirmed Fit bar and any fitment notes shown by the garage tool.

How does this reservoir match the original part?

Dorman engineered this reservoir to reproduce the original unit’s fit and functional points so mounting tabs, hose connections and cap sealing mimic factory geometry. The cap is pressurized and included, reducing the number of parts you need to source separately.

• Factory-like mounting locations for bolt-in installation.
• Correct hose port sizes and orientation for easy connection.
• Supplied with a pressurized cap to maintain proper coolant system pressure.
• Built from heat- and vibration-resistant thermoplastic for underhood durability.

What are the durability and quality features?

This reservoir is produced from materials chosen to resist underhood heat, coolant exposure and engine vibration. Dorman leverages long aftermarket experience to deliver parts designed for practical longevity and dependable performance in routine driving conditions.

• High-temperature thermoplastic construction resists warping and cracking.
• Vibration-tolerant design helps prevent stress fractures at mounting points.
• Preinstalled cap ensures correct sealing and system pressurization from day one.
• Manufactured and inspected to meet aftermarket fit-and-function expectations.

How do I install this coolant reservoir myself?

Installation is typically straightforward for anyone comfortable working in the engine bay. Basic steps include draining the recommended amount of coolant if needed, disconnecting hoses and sensors, unbolting the old reservoir, transferring any hardware or sensors as required, and bolting the new unit into place before refilling and bleeding the cooling system per manufacturer guidance.

• Park on a level surface and allow the engine to cool completely before starting.
• Disconnect negative battery terminal if accessing electrical connectors or sensors.
• Remove hoses and mounting bolts, transfer any sensors, then install the new reservoir.
• Refill coolant and run the engine to check for leaks and proper level; follow vehicle-specific bleed procedure.

Who is this for: Dorman 603-054 is intended for owners and technicians repairing Cadillac, Chevrolet or GMC full-size trucks and SUVs from the covered model years who need an OEM-style replacement coolant reservoir with cap. It’s a practical option when the original tank is cracked, leaking, warped or the mounting points are damaged, and when you want a ready-to-install unit that restores system containment and pressure without modifying the cooling system.