Gates 31539 Radiator Cap

OE Type Radiator Cap for Closed Cooling Systems

The Gates 31539 OE Type Radiator Cap is built for closed coolant bottle applications that require accurate pressure control and a threaded coolant bottle cap design. It is a direct-fit cooling system service part for select Ford, Mazda, and Mercury vehicles, including Escape, Tribute, Mariner, Cougar, Contour, and Mystique applications.

Gates OE Type Radiator Cap 31539 is engineered to meet OE performance expectations with corrosion-resistant construction and consistent sealing characteristics. The cap is specified at 17 psi and matches the filler neck dimensions used in the listed applications.

Key Features

• OE Type Radiator Cap for closed coolant recovery systems
• Threaded coolant bottle cap design
• 17 psi pressure rating with SAE pressure range of 15-18 psi
• Filler neck inside diameter: 1.53 in. / 39 mm
• Filler neck outside diameter: 1.97 in. / 50 mm
• Filler neck depth: 1.41 in. / 36 mm
• Shell diameter: 2.48 in.
• Corrosion-resistant metal or high-quality plastic construction, depending on application
• Built to meet or exceed OEM specifications in function, form, and fit

Product Details

This Gates radiator cap is part of the OE Type Radiator Cap line, which focuses on replacement parts that match original equipment requirements for cooling system pressure management. The 31539 is intended for vehicles using a closed system coolant bottle cap and is specified for OE performance. It is a practical replacement when servicing the cooling system on a 2001-2012 Ford Escape, 2001-2006 Mazda Tribute, 2008-2011 Mazda Tribute, 2005-2011 Mercury Mariner, 1999-2002 Mercury Cougar, 1998-2000 Ford Contour, or 1998-2000 Mercury Mystique.

This part cross-references Dorman - HELP 46059 and Four Seasons 33058 for the same application.

Common Problems This Part Can Address

• Loss of coolant system pressure
• Coolant overflow or recovery bottle venting issues
• Improper sealing at the coolant bottle neck
• Pressure-related overheating concerns
• Wear or corrosion on the original radiator cap

Installation Notes and Tips

• Verify the vehicle uses a closed coolant recovery system before installation.
• Confirm filler neck dimensions and pressure rating match the original specification.
• Inspect the bottle neck, sealing surfaces, and threads for damage before replacing the cap.
• Install on a cool engine and check for proper seating after tightening.
• Use the listed fitment to confirm application details for your Ford Escape, Mazda Tribute, or Mercury Mariner.

Quality Assurance

Gates manufactures this radiator cap to meet or exceed OEM specifications in function, form, and fit. The construction uses corrosion-resistant materials selected for long service life and accurate pressure control, with environmental regulatory standards in mind.