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Wastegate Rattle: Causes, How Serious It Is & How to Fix

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  • 5 min read

Last Updated on: 27th November 2023, 11:27 pm

For turbocharged vehicles, the term “wastegate rattle” may come up at some point.

It occurs when the actuator and valve begin to loosen, resulting in a noticeable knocking, clunking or rattling noise.

While it may not be an immediate issue, not fixing it can potentially lead to more significant problems.

In this article, we’ll explain what wastegate rattle is, what causes it, how serious it is and how you can fix it.

example of what wastegate rattle looks like

What Is Wastegate Rattle?

Wastegate rattle is an issue that arises when the wastegate valve and actuator produce a distinctive knocking or rattling sound.

  • Fast ticking/rattle when engine revs are falling
  • Noise occurring up to six or seven times in a row during a deceleration from approximately 3,500 RPM

If this is similar to what your vehicle sounds like, it may be wastegate rattle.

It can occur due to valve malfunction or actuator issues. It’s typically most noticeable during engine idling or acceleration.

The noise may become more pronounced when the vehicle is under increased load, like driving up a hill, towing a trailer, etc.

How Serious Is It?

While wastegate rattle is not usually a severe issue at first, it can be an annoyance for drivers and could potentially lead to other issues if left unfixed.

When the wastegate valve malfunctions, it may result in the turbocharger producing excessive boost pressure (called over-boost), potentially leading to engine damage.

Furthermore, it’s an indicator of the actuator not working properly.

If the actuator is not functioning correctly, it can adversely affect the wastegate valve’s operation, causing the turbocharger to produce either excessive or insufficient boost pressure.

The video below shows what wastegate rattle sounds like.

YouTube video

How to Fix

Fixing depends entirely on what car you have, however, below are some general options you may have.

  • The low-cost option is usually to remove the turbos and install new waste gates
  • Sometimes the wastegate and turbocharger are welded together and a whole new unit is required

What Happens if You Don’t Fix It?

Neglecting to fix wastegate rattle is likely to result in a progressive deterioration of the problem.

The noise could get worse, occur more often, and it has the potential to cause further problems involving the valve or actuator.

If it’s getting worse then the wastegate assembly will get looser and either not seal properly at initial spool up or it could stick open.

If left unfixed, the wastegate valve may become lodged in either the open or closed position.

Causes

Oftentimes wastegate rattle is caused over time, exhaust gas passing through the bypass collides with the face of the valve causing vibration, which is transmitted to the wastegate components, causing the issue.

However, there are other causes, such as those listed below.

1. Worn or damaged wastegate valve or actuator

When wear or damage affects the wastegate valve or actuator, it can result in these components becoming loose, causing a knocking or rattling noise.

2. Incorrectly adjusted actuator

If the wastegate actuator is not adjusted properly, it can disrupt the timing of the wastegate valve opening and closing, potentially resulting in this issue.

3. Loose or worn wastegate rod

When the wastegate rod, linking the actuator to the valve, is loose or worn, it can lead to unwanted movement in these components.

This unwanted movement can lead to the emergence of a knocking or rattling noise.

4. Excessive boost pressure

Excessive boost pressure generated by the turbocharger can result in the wastegate valve excessively opening and closing, potentially causing wastegate rattle to occur.

Excessive boost pressure, called over boosting, can be caused by many factors, including tuning and remapping.

diagram of components in a wastegate

How to Fix

Below are some possible ways to fix wastegate rattle.

  1. Inspect the valve and actuator for damage: Check for damage and replace or repair as needed.
  2. Adjust the wastegate actuator: Incorrect adjustment of the actuator can result in improper valve operation, causing wastegate rattle. Properly adjusting the actuator may fix it.
  3. Tighten the wastegate rod: If the wastegate rod is loose or worn, it can lead to unwanted movement, generating a knocking or rattling noise. Tightening the rod may resolve this.
  4. Reduce boost pressure: If the turbo produces too much boost pressure, it can lead to the valve opening and closing excessively, causing a rattle. Reducing the boost pressure may be needed.
  5. Clean the valve and actuator: If the valve and actuator accumulate dirt or debris, their functionality may be affected. Thoroughly cleaning these components can be a solution.
  6. Replace the wastegate spring: A worn or damaged wastegate spring can disrupt the timing of the valve’s operation, leading to wastegate rattle. Replacing the spring could help.

If these solutions don’t help, you may need to repair or replace the wastegate or related components.

References & More Information
  • Andy Lewin

    Andy Lewin is a senior mechanic, ASE qualified master technician, and an experienced automotive engineer. He's passionate about serving the automotive community with the highest-quality and trustworthy information on all things automotive. He loves to write about car repairs, maintenance, car modifications and tuning, faults, and much more.

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