have you checked if your engine is actually getting too hot? once the temp gauge reads red pull over and see if your engine is hotter than normal, the gauge might be dodgey because of the thermostat. as mentiioned above whats the condition of your thermostat? might be worth having a look at it. its only 3 bolts to undo it. i had a similar problem like this, changed the thermostat with a msd one and got a new rubber seal as the old one was f*cked. once it was changed i never had another problem with it the gauge telling me that the car was overheating