Hi, I've had my TR5 for 45 years so you'd have thought that there wouldn't have been a problem that I hadn't encountered before, wrong.... Car is cooled via Evans coolant & Kenlowe fan. At a stand still in the garage it ticks over nicely with the temperature hovering around the normal (mid-way) point on the gauge. The fan kicks in fine and maintains the temperature. However, take the car on the open road and almost immediately the temperature soars 'till it's "bending the needle".