mustafasahin

Hi Exactly the same sound my car does on idle. i was searching where it is coming from for months. Like you said it started after first 1k-2k km. Totally by chance i find it. As you said it is coming from the selenoid valve. But not because the valve itself ,where it is attached to. this valve is attached to the coolant expansion tank. When the valve starts working the valve vibrates the expansion tank.in my opinion as it is half with fluid the empty space magnifies the sound. in my car when you press the tank and valve with your hand the knocking sound stops. i will visit dealer next month. if they find a proper solution i will share it here. This is the valve and the tank where it is attached.