(G) water bottle greeny/yellow white bits bits

just purchased fiat stilo abarth and checked water bottle and in the cap its has a greeny layer or mould and little greeny/yellow/white hard bits, could anyone please give me any advice on if this could be the start of a new head gasket its done 70,000 miles and doesnt get driven much.help would be realy appreciated?theyre arent any in the water itself just in the cap and on rim of bottlw thankuou.

The coolant has probably just been hanging about a bit, like you say. If you have a head gasket going you'll know all about it, engine overtemping, white smoke out exhaust, coolant reservoir overflowing with scalding water, heater blowing cold, air sounds and gurgles in the water hoses, not starting on all 5 cylnders when cold. Take your pick- mix and match


Coolant reservoir is easy to get off so see if you can clean it out

maybe your right,your advice certainly makes sense.thanks very much have just bought it and am learning slowly