Dear Auto experts in the house,

I drive an opel Vectra B 2000 model. I experienced instant engine overheating few months back. This was traced to a faulty (burnt) radiator fan. This was replaced but temperature still reads at 90 degree Celsius as against 80 which was my normal reading from time. Engine was later changed last month as a result of other complications.

However, the new engine has inherited same symptoms of temperature gauging at 90 degrees with check engine light popping up with intermittent jerking. I also noticed that driving the car on express road reduces the temperature to 85 degrees.

The radiator has been washed, cooling fan replaced again but symptoms still persistent.

I am almost confused and will appreciate assistance from auto gurus in the house.

Thanks.
Note: The car drives fine as long as temp is not above 80 and without check engine light.