Hi i have an N Reg escort 1.4 and if im sat still in traffic or anywhere for to long the coolant tank starts to steam, i have driven around init all day yesterday and not a single issue but today i was caught in traffic and it started to steam, this happened a few days ago at the garage where they had the engine running but car not moving and then started to steam then aswell, this is my first ford so all help and suggestions would be great

thanks