Ford Focus MK2 Mondeo MK4 1.8 TDCi Crankcase Breather Vent Pipe 4M5Q-6K666-AA

Ford Focus MK2 Mondeo MK4 1.8 TDCi Crankcase Breather Vent Pipe is an original component of the crankcase ventilation system, designed for use in Ford power units. Thanks to its factory geometry and fitment, it ensures proper circulation of oil vapors and stable engine operation under various operating conditions. It is a practical solution for users who want to restore the correct operation of the breather system using a dismantled part.

Specifications and technical data

• SKU: 4M5Q6K666AA
• Mark: Ford
• Condition: Used
• OEM Part Number: 4M5Q-6A804-AC
• Substitutable numbers: 4M5Q-6K666-AA, 4M5Q6K666AA
• Category: Air Pipes & Hoses

Function and role of the breather pipe in the Ford Focus MK2 Mondeo MK4 1.8 TDCi Crankcase Breather Vent Pipe

The breather pipe in the Ford Focus MK2 Mondeo MK4 1.8 TDCi Crankcase Breather Vent Pipe is responsible for the controlled discharge of oil vapors from the crankcase into the intake system. A properly selected component:

• stabilizes pressure in the crankcase,
• reduces blow-by and uncontrolled oil leaks,
• supports smooth engine operation at idle and under load,
• reduces the risk of intake contamination with excess oil.

By maintaining the factory shape and connection diameters, the breather pipe allows for trouble-free installation in place of the original component, without the need for system modifications.

Why it is worth using an original Ford breather pipe

In the engine ventilation system, tightness, temperature resistance, and compliance with the factory design are crucial. Using an original Ford breather pipe ensures:

• secure fitment to the connectors and mounts in the engine bay,
• appropriate material flexibility within typical operating temperature ranges,
• maintenance of proper vapor flow without uncontrolled turbulence,
• compatibility with the factory engine management system.

For users planning comprehensive maintenance of the powertrain using used parts, broader tips on evaluating dismantled components may also be useful – you can find them in our guide on the safe selection of used powertrain and accessory components.

Characteristics of the used part

The offered breather pipe is a dismantled part, which allows for economical repair while maintaining the original design specification. A component of this type is particularly useful when:

• the factory pipe has cracked or delaminated,
• there are oil leaks in the vicinity of the breather,
• the engine is running unevenly due to leaks in the ventilation system.

During installation, it is recommended to check the condition of the connectors, clamps, and adjacent hoses to fully utilize the potential of the replaced component and avoid further leaks.

Practical installation and operating tips

To ensure the replacement of the breather pipe in the Ford Focus MK2 Mondeo MK4 1.8 TDCi Crankcase Breather Vent Pipe is effective and durable, it is worth paying attention to a few technical aspects:

• clean the mating surfaces and connectors of oil deposits before installation,
• check that the pipe is not twisted or excessively tensioned after installation,
• use appropriately selected hose clamps if the design requires it,
• after starting the engine, check the system for leaks at various RPMs.

This approach helps maintain stable engine operating parameters and reduces the risk of recurring faults related to the breather system.

Summary

Ford Focus MK2 Mondeo MK4 1.8 TDCi Crankcase Breather Vent Pipe is a practical solution for drivers who want to restore the proper operation of the engine ventilation system using an original dismantled part. A properly selected and correctly installed pipe supports smooth engine operation, reduces oil leaks, and helps maintain proper conditions in the crankcase, which translates into more predictable and comfortable vehicle operation.