Gates 31538 Radiator Cap

OE Type Radiator Cap for Closed Cooling Systems

The Gates 31538 OE Type Radiator Cap is built for closed coolant recovery systems that require a threaded coolant bottle cap with a 15 psi pressure rating. It is a direct-fit cooling system service part for select Dodge Sprinter 2500, Dodge Sprinter 3500, Jeep Cherokee, Jeep Comanche, and Jeep Wagoneer applications.

Gates OE Type Radiator Cap 31538 is manufactured to meet or exceed OEM specifications for function, form, and fit. The cap uses corrosion-resistant construction and is engineered for accurate pressure control in the cooling system.

Key Features

• OE Type Radiator Cap for closed coolant recovery systems
• Threaded coolant bottle cap design
• 15 psi pressure rating with SAE pressure range of 14-18 psi
• Corrosion-resistant metal or high-quality plastic construction, depending on application
• Filler neck inside diameter: 1.49 in. / 38 mm
• Filler neck outside diameter: 1.57 in. / 40 mm
• Filler neck depth: 0.94 in. / 24 mm
• Shell diameter: 2.13 in.
• OE Performance comparison rating

Product Details

This Gates radiator cap is made for vehicles that use a closed system coolant recovery setup and a threaded bottle-style cap. The 31538 helps maintain proper system pressure, which is critical for stable coolant operation and consistent cooling performance. It is a practical replacement for owners servicing a 2006-2009 Dodge Sprinter 2500, 2006-2009 Dodge Sprinter 3500, or 1987-1990 Jeep Cherokee, Comanche, or Wagoneer cooling system.

This part cross-references Dorman - HELP 46070 and Four Seasons 33069 for the same application. Gates 31538 is also listed under interchange references including 703-1650 and T-35.

What This Part Helps Address

• Coolant loss caused by a cap that no longer holds pressure
• Overheating related to weak or inconsistent cooling system pressure
• Steam or overflow from a worn radiator or coolant bottle cap
• Pressure retention issues in a closed coolant recovery system
• Fitment problems when replacing an OE-style threaded bottle cap

Installation Notes and Tips

Verify the filler neck dimensions, pressure rating, and closed-system design before installation. This Gates 31538 radiator cap is specified for a threaded coolant bottle cap application, so the neck style and depth should match the vehicle’s original setup. Confirm fitment for your exact year and model before service, especially on Dodge Sprinter and Jeep cooling system repairs.

Quality Assurance

Gates manufactures this OE Type Radiator Cap to meet or exceed OEM specifications in function, form, and fit. The cap is built with corrosion-resistant materials to support long service life and accurate pressure control while meeting environmental regulatory standards.