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 crankcase ventilation system component designed for use in Ford engines. Thanks to its factory geometry and fitment, it ensures stable crankcase gas routing, which promotes smooth engine operation and reduces the risk of leaks. It is a practical solution for users who want to restore the efficiency of the breather system in their Mondeo MK4 in a technically correct manner.

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

Purpose and function of the breather pipe

The presented pipe is a component of the crankcase ventilation system, responsible for the controlled discharge of oil vapors and gases from inside the engine for further processing in the intake system. A properly selected breather pipe helps limit overpressure in the crankcase, which translates into stable seal performance and reduces the risk of oil leaks.

Thanks to a design consistent with Ford's factory solutions, the pipe maintains the correct diameter and shape, which facilitates installation in original mounting points and ensures proper gas flow throughout the system.

Benefits of using an original Ford component

Using an original Ford component allows you to maintain technical consistency with other engine system elements. In practice, this means:

• secure fitment to factory connectors and brackets,
• maintenance of the flow capacity designed by the manufacturer,
• reduced risk of improper installation compared to universal replacements.

For users who care about the proper operation of the engine, this is a solution that helps maintain stable engine performance parameters and facilitates future diagnostics.

Characteristics of the used component

The offered breather pipe is a used part, sourced from vehicle dismantling. Such a component, provided it maintains adequate tightness and flexibility, can be an economical way to restore system efficiency without the need to invest in a new part. In practice, this allows for lower repair costs while maintaining the original pipe design.

Choosing a used breather pipe is particularly justified for vehicles used on a daily basis, where it is crucial to combine reasonable service costs with the maintenance of proper engine system functionality.

Application in restoration and maintenance of youngtimers

The fourth-generation Ford Mondeo is increasingly being treated as a car worth maintaining in good technical condition for a long time. Properly selected used mechanical parts, such as the breather pipe, allow for the gradual restoration of the vehicle without excessive budget strain. You can find more about the approach to rejuvenating older cars using parts from dismantling in the article The second life of a youngtimer – how used parts help rejuvenate cars from the turn of 1998–2012.

Why it is worth considering a used part

In the case of elements such as the breather pipe, it is often crucial to maintain the original geometry and compatibility with the rest of the system, which speaks in favor of choosing a component from factory production. A used part can be a rational compromise between cost and quality, especially when it comes from a reliable source.

If you are wondering when it is better to choose a new subassembly and when to choose a dismantled element, the guide Car parts – new or used? A comparison of costs and durability may be helpful, in which practical scenarios for selecting parts depending on the type of repair and the age of the vehicle are discussed.