Calorstat RC0036 Engine Coolant Reservoir Cap

Engine Coolant Reservoir Cap for Porsche and Audi

Calorstat RC0036 is a threaded engine coolant reservoir cap built with plastic and rubber for pressurized cooling systems. It is rated to 22.0 psi and is used on a wide range of Porsche and Audi applications, including Porsche 911, Boxster, Cayman, and select Audi A8, A8 Quattro, S6, S8, A4, A6, and Cabriolet models.

Key Features

• Part number RC0036 engine coolant reservoir cap
• Pressurized design with a 22.0 psi maximum pressure rating
• Threaded attachment type for secure reservoir fitment
• Plastic and rubber construction for cooling system sealing
• Standard cap design with no pressure release lever
• Compatible with select Porsche and Audi cooling system applications

Product Details

This Calorstat RC0036 coolant reservoir cap is a direct-fit style service part for pressurized expansion tanks and coolant reservoirs. It is listed for OEM recommended applications on Porsche 718 Boxster, 718 Cayman, 718 Spyder, 911, Boxster, and Cayman models, and it also cross-references Anchor 10225 for the same application. The RC0036 is also used across multiple Audi platforms where the cooling system requires a threaded, pressurized cap with a 22.0 psi rating.

For fitment-based searches, this part is commonly selected for Porsche 718 Cayman coolant reservoir cap replacement, Porsche Boxster coolant reservoir cap service, and Audi A8 Quattro coolant reservoir cap applications. The RC0036 part number is also referenced in OE-style replacement searches for Porsche and Audi cooling system maintenance.

Common Issues This Part Can Address

• Coolant loss from a worn or damaged reservoir cap seal
• Cooling system pressure loss caused by a weak cap spring or seal
• Improper reservoir sealing on threaded expansion tanks
• Coolant odor or residue around the reservoir cap area
• Pressure-related cooling system warning symptoms tied to cap failure

Installation Notes and Tips

Verify the reservoir neck style, thread pattern, and pressure rating before installation. Inspect the coolant reservoir sealing surface for cracks, debris, or hardened residue, and confirm the cap seats fully by hand without cross-threading. After installation, check the cooling system for leaks and confirm the cap matches the vehicle’s specified pressure requirement.

Quality Assurance

Calorstat supplies cooling system components for OE-style service applications, and this RC0036 cap is specified for OEM recommended fitments on select Porsche and Audi vehicles. Confirm vehicle year, make, model, and reservoir configuration against the listed applications before ordering.

Compatible Vehicles

• Fits 2025 Porsche 718 Boxster, N/A, OEM Recommended
• Fits 2024-2025 Porsche 718 Cayman, N/A, OEM Recommended
• Fits 2025 Porsche 718 Spyder, N/A, OEM Recommended
• Fits 2021-2023 Porsche 718 Cayman, N/A, On Reservoir
• Fits 2013-2016 Porsche Boxster, N/A, Pressure Rating: 1,5bar - 22psi
• Fits 1997 Porsche Boxster, N/A, Pressure Rating: 1,5bar - 22psi
• Fits 2014-2016 Porsche Cayman, N/A, Pressure Rating: 1,5bar - 22psi
• Fits 1999-2013 Porsche 911, N/A, OEM Recommended
• Fits 1998-2012 Porsche Boxster, N/A, OEM Recommended
• Fits 2006-2012 Porsche Cayman, N/A, OEM Recommended
• Fits 1997-2003 Audi A8 Quattro, N/A, Vernet is an OE Supplier to Audi
• Fits 2001-2003 Audi S8, N/A, Vernet is an OE Supplier to Audi
• Fits 1997-1999 Audi A8, N/A, Vernet is an OE Supplier to Audi
• Fits 1995-1998 Audi Cabriolet, N/A, Vernet is an OE Supplier to Audi
• Fits 1995-1997 Audi A6 Quattro, N/A, Vernet is an OE Supplier to Audi
• Fits 1995-1997 Audi S6, N/A, Vernet is an OE Supplier to Audi
• Fits 1996 Audi A4, N/A, Vernet is an OE Supplier to Audi
• Fits 1995-1996 Audi A6, N/A, Vernet is an OE Supplier to Audi
• Fits 1995 Audi 90, N/A, Vernet is an OE Supplier to Audi
• Fits 1995 Audi 90 Quattro, N/A, Vernet is an OE Supplier to Audi