need to know asap as i have no car now, no fun in this bloody snow and ice.
I have a diesel a170 avant garde and have put £20 of petrol in the the bloody thing and drove it about 8 miles before it conked out on an A road urghhhh!!!!!
How do I drain and do i need to change any parts ?????????

I once put gas in my diesel sprinter van and drove about 5 miles and it conked out. It was towed and fuel tank drained and they did something else I can't remember but 1000.00 dollars later it was fixed. The tow plus mechanic's charge may be different where you are. Good luck.

parts that need changing now are the engine,sorry the damage has been done ,call a mercedes dealer,as soon as the engine is started the damage is done

get it up off the ground enough to get a container big enough to hold fuel, disconnect fuel line after fuel pump, turn on ignition key and let it pump out fuel