Causes of Turbo Wastegate Problems
Turbo wastegate failures can be caused by a variety of underlying issues, some of which are not always easy to identify. However, it is important to learn how to troubleshoot such issues to prevent wastegate failures from recurring. Below are some of the most common causes of turbo wastegate failures:
1) Carbon Deposits
In some cases, carbon buildup can cause the wastegate to fail. A bypass often occurs because carbon produced by the exhaust gases contaminates the inner membrane of the wastegate. In extreme cases, this carbon contamination can even cause the wastegate’s inner membrane to burst.
2) Weak actuator spring
Turbo wastegates can fail due to normal wear and tear when the actuator spring begins to deteriorate. When this happens, the wastegate can start venting unexpectedly, causing boost pressure instability.
3) Misaligned
In some cases, both the internal and external wastegates may need to be adjusted. This procedure varies depending on the wastegate configuration. If the wastegate is not set up correctly, it can cause many operational problems.
Where is the wastegate?
There are currently two different types of turbocharger wastegates in use: internal and external.
This type of wastegate typically has a pneumatic actuator, a flapper valve, a crank arm, and a rod end. Alternatively, some turbochargers feature an externally mounted wastegate between the engine’s exhaust manifold and the turbo’s intake turbine housing.
This type of wastegate reduces intake air consumption by redirecting the incoming exhaust gases when boost pressure exceeds the rated value.
Wastegate vs. Blow-Off Valve
Both wastegates and blow-off valves are designed for use on turbocharged engines and are designed to reduce the risk of overboost. However, the use of these two components differs slightly from each other, mainly in terms of the location of the two components. As mentioned above, wastegates are located in front of the turbocharger, along the engine’s exhaust manifold, or in the turbine housing of the turbocharger itself.
A blow-off valve, on the other hand, is located downstream of the turbocharger itself in the engine’s intake tract. These devices divert excess boost pressure rather than preventing it from building up like a wastegate does.
Do all turbo cars have wastegates? Turbo engines and wastegates go hand in hand, and most turbo engines have some type of wastegate. However, there are some exceptions to this general rule, the most common of which include the newer, more advanced variable geometry turbochargers.
Variable geometry turbochargers are unique in that they provide many of the same wastegate functions without the use of a special wastegate.
This type of turbocharger has special vanes on the exhaust side that move in response to different operating conditions. This movement redistributes the flow of incoming exhaust gases, slowing down the overall speed of the turbocharger.
Can I run a turbo without a wastegate? Most turbo engines produced today use some form of wastegate. This is because the wastegate acts as a type of engine protection device and prevents overcharging from occurring.
Without this protection, serious engine damage could occur when the turbo engine reaches its top speed. While it is theoretically possible to run a turbo engine without a wastegate, this is rarely practical.
To achieve this, you need to find the perfect turbo for your specific application, one that will only reach the engine’s maximum boost pressure threshold at top speed.
What is wastegate rattle? Wastegate rattle is a condition in which an engine’s turbocharger produces a persistent “ringing” or “chilling” noise. This noise is most often heard when the engine is idling, but can also be heard during slight acceleration.
In most cases, wastegate rattle is more prevalent in engines with high mileage. Like many other turbocharger issues, wastegate rattle is most often caused by excessive wear that accumulates over the life of the turbo.
This “rattle” comes from the wastegate itself, caused by worn bushings and actuator rod ends within it. As a result of this wear, the wastegate no longer seats tightly, causing the rattle you hear.