Calorstat RC0039 Engine Coolant Reservoir Cap

Engine Coolant Reservoir Cap for OE-Style Cooling Service

The Calorstat RC0039 engine coolant reservoir cap is a threaded, pressurized replacement cap built for cooling systems that require an 18 PSI opening pressure. Made from plastic and rubber, it provides a standard-style seal for maintaining proper coolant system pressure on select Chevrolet, Pontiac, Saab, Ford, and Mercury applications. This Calorstat RC0039 coolant reservoir cap is a direct-fit service part for vehicles such as the Ford Focus, Saab 9-3, and Chevrolet Aveo.

Key Features

• Engine coolant reservoir cap with threaded attachment type
• Standard design with pressurized operation
• 18 PSI opening pressure and 18.0 maximum pressure rating
• Plastic and rubber construction for sealing performance
• No pressure release lever
• OE-style replacement for select cooling system applications

Detailed Description

The Calorstat RC0039 is a pressure cap for the coolant reservoir, used to help maintain the correct pressure level in the cooling system. Its 18 PSI rating matches applications that specify a 1.2 bar cap, including 2000-2003 Ford Focus and 1995-1997 Ford Contour and Mercury Mystique models with the listed pressure requirement. It also serves select Saab 900, Saab 9-3, Saab 9-5, Chevrolet Aveo, Chevrolet Aveo5, Pontiac G3, Pontiac G3 Wave, Pontiac Wave, and Pontiac Wave5 applications. This part cross-references Gates 31530 for the same application.

What It Helps Address

• Coolant loss from a worn or weak reservoir cap seal
• Pressure-related overflow in the expansion tank
• Improper cooling system pressure retention
• Cap fitment issues on threaded coolant reservoirs
• Service replacement for aging OE-style cooling hardware

Installation Notes and Fitment

Install on a clean, undamaged coolant reservoir neck and verify the cap threads fully engage before driving. Confirm the vehicle uses an 18 PSI / 1.2 bar specification before replacement. Fits 2004-2011 Chevrolet Aveo, N/A; Fits 2006-2011 Chevrolet Aveo5, N/A; Fits 2009-2010 Pontiac G3, N/A; Fits 2009 Pontiac G3 Wave, N/A; Fits 1999-2009 Saab 9-5, N/A; Fits 2005-2008 Pontiac Wave, N/A; Fits 2005-2007 Pontiac Wave5, N/A; Fits 2004 Ford Focus, N/A; Fits 2000-2003 Ford Focus, N/A; Fits 1999-2003 Saab 9-3, N/A; Fits 1998 Ford Contour, N/A; Fits 1998 Mercury Mystique, N/A; Fits 1994-1998 Saab 900, N/A; Fits 1995-1997 Ford Contour, N/A; Fits 1995-1997 Mercury Mystique, N/A.

Quality Assurance

Calorstat is listed as an OE supplier to GM for several of the covered applications, supporting factory-style fit and pressure specification alignment. Part number RC0039 is also known under common interchange references used in cooling system service, including RC201 and RC227.