Fel-Pro 35555 Engine Coolant Thermostat O-Ring

Fel-Pro 35555 Engine Coolant Thermostat O-Ring

Fel-Pro 35555 is a premium black engine coolant thermostat O-ring built for sealing accuracy in cooling system service. It is sized for applications that call for a 2.365 inside diameter, 2.675 outside diameter, and 0.155 thickness, helping restore a tight seal at the thermostat housing.

Compatible With Toyota Tundra, Toyota 4Runner, Toyota Sequoia, Lexus GX470, Lexus LX470, Lexus SC430, Hyundai Santa Fe, and other listed applications, this Fel-Pro thermostat O-ring supports dependable cooling system sealing across a wide range of import vehicles.

Key Features

• Fel-Pro part number 35555
• Engine coolant thermostat O-ring for cooling system sealing
• Black premium-grade construction
• Inside diameter: 2.365
• Outside diameter: 2.675
• Thickness: 0.155
• Application-specific sealing material selection
• Built for vehicle-specific thermostat housing service

Detailed Description

Fel-Pro 35555 is an OE-style sealing component for thermostat housing service where a precise coolant seal is required. Fel-Pro states that its gasket and sealing products are engineered for complete vehicle sealing using application-specific materials, and this O-ring follows that approach with dimensions matched to the listed fitments. It is a practical choice for maintenance on vehicles such as the Toyota Tundra, Toyota 4Runner, and Lexus GX470, as well as many Kia, Hyundai, Mitsubishi, Mazda, and Chrysler/Dodge applications.

This part cross-references MAHLE C31348 for the same application.

What It Helps Address

• Coolant seepage at the thermostat housing
• Sealing wear from heat cycling and age
• Loss of coolant system pressure at the thermostat interface
• Service replacement for hardened or flattened O-rings
• Leak-related overheating concerns tied to thermostat housing sealing

Installation Notes and Tips

• Confirm the thermostat housing groove and mating surfaces are clean before installation.
• Inspect the old O-ring for flattening, cracking, or hardening to verify replacement need.
• Use the listed dimensions and vehicle fitment to confirm the correct application before assembly.
• Apply coolant-compatible lubricant only if specified by the service procedure.
• Recheck the cooling system after installation for leaks and proper coolant level.

Quality Assurance

Fel-Pro sealing products are known for application-specific fit and material selection in professional engine service. Part number 35555 is built as a premium sealing component for the listed vehicle applications and cooling system repair work.