Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

hi i drove my 1.2 twist yesterday for lyk 30mins all was fine un till 20 mins my temp gauge raised to 100 thwen the fan kicked in and still the gauge readin highh?? even on idle the engine is over heating?? my oil is fine ... tbh tho the other day i did put a bit over the cold in my compressiion tank , i dunno if this is makin this situation.. ive been told change my thermostate but my car was fine till i did this the other day.. helpp pleaseeeeeeeeee .. dannooo