Why does the engine still make noise after the Tiguan is turned off?
2 Answers
When the Tiguan is turned off and the engine is still making noise, it is actually the sound of the fan. The Tiguan is equipped with a turbocharged engine, and for turbocharged vehicles, the fan continues to operate for cooling after the engine is turned off, which is a normal phenomenon. Below is relevant information about turbocharged engines: 1. When using a turbocharged engine model, it is important to note that after parking, do not turn off the engine immediately. While the engine is running, some of the oil is supplied to lubricate the turbocharger rotor bearings and for cooling. If the engine is suddenly turned off while running, the oil pressure rapidly drops to zero, and the high temperature from the turbocharger turbine section transfers to the middle, preventing the heat in the bearing support housing from being quickly dissipated. Meanwhile, the turbocharger rotor continues to spin at high speed due to inertia. Therefore, suddenly turning off the engine while it is hot can cause the retained oil in the turbocharger to overheat and damage the bearings. 2. After the engine has been running under heavy load for an extended period, it should idle for 3-5 minutes before being turned off to allow the turbocharger rotor speed to decrease, especially avoiding sudden shutdown after revving the engine. After starting the engine, especially in winter, it should idle for a while to ensure the bearings are fully lubricated before the turbocharger rotor reaches high speed.
I'm a seasoned Tiguan driver, and it's quite common to hear noises from the engine bay after turning off the car. Last week, my car did the same, and upon closer inspection, I found it was the turbocharger cooling down. That thing can reach working temperatures of 500-600 degrees, so the cooling fan automatically runs for a few minutes after shutdown to cool it. There's also the ticking sound from the exhaust pipe due to thermal expansion and contraction, like popping beans. But you need to be careful to distinguish: if it's still making noise after more than five minutes, you should check if the electronic water pump is stuck. My neighbor's car had a faulty water pump last time, causing abnormal noises due to coolant not circulating. Here's a little trick to tell: if there's a burnt smell or the noise is particularly harsh, it's safer to get it checked at the dealership immediately.
