Why does the BMW X5 make loud exhaust noise during cold start?
2 Answers
BMW X5 makes loud exhaust noise during cold start because the engine oil inside flows back to the oil pan when the car is cold, and the idle speed is also higher during cold start, so the engine noise feels louder when the car is just started. The noise will return to normal after the engine temperature rises, which is a normal phenomenon. The BMW X5 is the first four-wheel drive SUV model of the BMW brand, achieving unprecedented levels in technical equipment and performance for four-wheel drive vehicles. The car has excellent handling sensitivity and stability, and adopts a series of innovative technologies, including four-wheel braking, ASCT (Automatic Stability and Traction Control), and DSCIII (Automatic Dynamic Stability Control).
It's quite common for the BMW X5 to have a loud exhaust sound during cold starts. As someone who frequently repairs this model, I've found it's mainly due to the deliberate design of the engine management system. During cold starts, the engine revs higher to quickly heat up the catalytic converter for optimal operation, which results in a loud roaring sound from the exhaust system. The X5's exhaust valve design is also unique—initially, the valve opens to increase airflow, creating a growling noise. After a few dozen seconds, when the RPM drops, the sound normalizes and there's no issue. This type of noise is standard practice in BMW vehicles, prioritizing performance and efficiency. If the sound remains loud or there are unusual noises while driving, it's necessary to check for leaks in the muffler or exhaust pipes, or if the valve is stuck. Regular maintenance, such as oil changes and carbon deposit cleaning, along with avoiding low-quality fuel, helps prevent issues.
