Advertised my Z4 on Autotrader - within an hour I received a call (which in itself I thought slightly odd). The gentleman, who had an Eastern European accent called himself Tim and wanted to view the car that day - which I agreed to. Shortly afterwards, I received a text from Autotrader advising the number I received the call from was associated with scams and to cease all further communication with them. I rang Autotrader to check their text was genuine and it was. Apparently 3 or 4 of then turn up to inspect your car and look under the bonnet. Whilst you doing that one of them squirts old oil up your exhaust. then the "buyer" asks to see in the boot and whilst you do that one of them then squirts oil into the coolant and water into the oil. This then makes the exhaust smoke/smell when you take them for a test drive and they claim car is only worth scrap and offer you a fraction of what it's worth !