I have a Honda Civic 2018, and for the past few days there has been a whistling sound coming from its engine. This sound doesn't occur during a cold start it starts around 10 minutes after the engine is running and the car has warmed up. After that, the sound disappears once the car has maintained its temperature. Sound is more prominent when we accelerate the car and rpm is decreasing. What could be the problem please assist me thankyou