I have a 525i which is overheating also. I am aware of the coolant system bleed procedure, but I have no idea where the bleeder screw is located on my engine. A friend states that on the 3 Series, the screw is on the thermostadt housing. I don't see anything that looks like a bleed screw on the 6 cylinder motor. Can you help? I hate that its something so simple but eludes me.