im from austria and own a '99 GTi6
its imported from germany and has at least 2 pre owners
and i got a problem with the temperature
when i drive outside the city far away from trafficlights and stop signs, the engine keeps cool between 70 and 90 degree celsius
but as i come into the city and stop&go phases, the engine heats up to 90° and over
the pre owner added a fan switch for switching the fan on manually
it cools automatic on his own, this switch is only for additional switch-on-the-fan
after switching on or driving faster than about 50 km/h / 30mph the engine cools down again
i own the car now a month and im afraid of summer when its hot outside
what are possible solutions for my problem?
(excuse my partially bad grammar , thx )