Mahle C33399 Engine Coolant Pipe O-Ring

Engine Coolant Outlet O-Ring for Ford Applications

The Mahle C33399 engine coolant outlet O-ring is an OEM-standard sealing component made from molded rubber for reliable coolant system sealing. It is specified for the coolant hose to degas bottle connection and engine coolant outlet service on select Ford and Lincoln vehicles.

Mahle’s Engine Coolant Outlet O-Ring line focuses on precise sealing performance for cooling system repairs, using materials and dimensions that match OE-style service requirements.

Key Features

• Molded rubber construction with a black finish
• Inside diameter: .862 in.
• Thickness: .144 in.
• OEM standard item grade for service replacement use
• Includes coolant hose to degas bottle O-ring application detail
• Cross-references Ford FL3Z-8590-A, FL3Z-8590-B and Motorcraft RTS-1085

Detailed Description

Mahle C33399 is an engine coolant pipe O-ring built for sealing the coolant hose to degas bottle connection and related coolant outlet service points. The molded rubber design helps maintain a tight seal in the cooling system, where correct dimensions and material consistency are critical for preventing leaks. This part is a direct service choice for 2015-2023 Ford F-150, 2017-2022 Ford F-250 Super Duty, 2017-2022 Ford F-350 Super Duty, 2018-2023 Ford Expedition, and 2018-2023 Lincoln Navigator applications. If you are replacing a Ford F-150 coolant hose to degas bottle O-ring or servicing a Ford Expedition engine coolant outlet seal, C33399 provides an OE-standard replacement path.

What It Helps Fix

• Coolant seepage at the hose-to-degas bottle connection
• Loss of sealing at the engine coolant outlet
• Leak-related coolant odor or residue around the fitting
• Service issues caused by a flattened, hardened, or damaged O-ring
• Cooling system maintenance on Ford F-150, Expedition, Navigator, and Super Duty trucks

Installation Notes and Tips

Inspect the sealing surfaces before installation and remove any old coolant residue, debris, or damage that could affect the seal. Confirm the replacement O-ring matches the original dimensions and application before assembly. Lubricate the O-ring with clean coolant or an approved assembly lubricant during installation to reduce twisting and help the seal seat evenly.

Quality Assurance

Mahle gaskets and sealing products are used by OEMs and technicians worldwide, and this part is built to OEM standard specifications for cooling system service.