BMW 525i Air Intake Hose

What is the hose connected to the air intake? 

An air intake hose, also called an air cleaner intake hose, is a flexible rubber or plastic tube that connects the air filter box or intake manifold to the throttle body or carburetor of an internal combustion engine. The primary function of an engine air intake hose is to carry fresh, filtered air from the air filter box to the engine to support combustion. Some air intake hoses also contain resonators or silencers to reduce intake noise, while others may incorporate sensors for measuring the air flow or temperature. Air intake hoses are usually made of heat-resistant materials to withstand high engine temperatures and exposure to hot, dry air that passes through the engine bay.

Air intake hose leak symptoms

• Smell of gasoline: A leaky air cleaner intake hose can allow excess air to enter the engine, leading to a rich fuel mixture. This can cause a strong smell of gasoline inside or outside the vehicle.
• Dirty air filter: If the engine air intake hose is leaking, dirt and debris can bypass the air filter and enter the engine, causing it to run inefficiently. This can result in a dirty air filter that needs to be replaced more frequently.
• Engine hesitation: An air filter hose leak can cause the engine to hesitate or stall when the accelerator pedal is pressed, especially at high speeds.
• High-pitched squeal: A leaking air filter intake hose can create a high-pitched squeal or whistling noise as air escapes from the hose.

How to replace the air intake hose?

An air cleaner intake hose can become cracked, torn, or loose as time goes by, which can affect the engine's performance and fuel efficiency. When you have detected the failure symptoms listed above, you may consider replacing your car’s air intake hose.

Refer to the steps below:

1. Locate the air intake hose between the air filter housing and the throttle body or mass airflow sensor.
2. Loosen the clamps or bolts that hold the old air intake hose in place.
3. Remove the old air intake hose.
4. Install the new air intake hose by attaching it to the air filter housing and the throttle body or mass airflow sensor.
5. Tighten the clamps or bolts to secure the new air intake hose in place.
6. Start the engine and check for any air leaks or abnormal sounds.