Dorman 54221 Engine Coolant Reservoir Cap

Reliable Engine Coolant Reservoir Cap for Cadillac, Oldsmobile, Pontiac

The Dorman 54221 engine coolant reservoir cap is designed to maintain proper pressure and ventilation in your vehicle's cooling system. Compatible with select Cadillac, Oldsmobile, and Pontiac models, this cap ensures efficient coolant containment and system protection.

• Durable black plastic construction
• 51 mm diameter for precise fitment
• Spring loaded twist type with threaded attachment
• Maximum pressure rating of 18 psi for optimal system performance
• Vented and pressurized design with pressure release lever
• Compact size: 2.5 inches in length and width
• Includes one coolant reservoir cap per package

Product Details and Specifications

The Dorman 54221 coolant reservoir cap is engineered with a spring loaded twist mechanism and threaded attachment to securely seal the coolant reservoir. Its black plastic material offers resistance to heat and corrosion, suitable for the cooling systems of Cadillac Aurora, Oldsmobile Aurora, Pontiac Bonneville, Cadillac DeVille, and Cadillac Eldorado models. The cap’s 51 mm diameter and 2.5 inch dimensions ensure a proper fit and reliable sealing. Designed to handle a maximum pressure of 18 psi, it helps maintain the correct pressure balance within the cooling system. The vented and pressurized design includes a pressure release lever to safely release excess pressure, preventing damage to the cooling system components.

Common Applications and Problem Resolution

• Prevents coolant leaks caused by worn or damaged reservoir caps
• Maintains proper pressure to avoid overheating and coolant loss
• Ensures safe pressure release to protect hoses and radiator
• Replaces cracked or broken caps that compromise cooling system integrity
• Restores venting function to prevent vacuum formation in the reservoir

Installation Notes and Tips

Installation of the Dorman 54221 coolant reservoir cap is straightforward due to its threaded attachment and spring loaded twist design. Before installation, ensure the engine is cool to avoid injury from hot coolant or steam. Remove the old cap by twisting counterclockwise, then align and thread the new cap clockwise until securely tightened. Verify that the pressure release lever moves freely and the cap is seated properly to maintain system pressure. Regular inspection of the cap during routine maintenance can help identify wear or damage early.

Quality Assurance and Warranty Information

Dorman parts are manufactured to meet or exceed OEM standards for fit, form, and function. The 54221 coolant reservoir cap undergoes quality checks to ensure durability and reliable performance in compatible Cadillac, Oldsmobile, and Pontiac vehicles. While specific warranty details may vary, Dorman typically offers limited warranties covering defects in material and workmanship. Consult product documentation or the supplier for exact warranty terms.