check all caps for chocolate , oil filler cap ,radiator cap, dipstick ,and steam trough exaust,
when the car is cold start it and touch the top water hose ,if it feels with a lot of
pressure when u just started the car , the head gasket is cracked to a piston and you wont
see no chocolate . but the car will steam a little trough the exhaust. bimmer heads
are good ,i have changed a lot and only seen one cracked , if you check all above
and pass

then buy it if the price is right ,