Is the cooling over 200 km/hr a common problem? I notice when driving 220 km/hr, after 10 minutes I have temperatures creeping up. When I slow down under 200 the temps go down accordingly. Speeding up again, and again the temps climb up. At lower speed and in the city all is normal. Now this is even with the recored radiator, and the system being cleaned. I am wondering could this be cavitation and will a different waterpump will fix the problem?

 

You need to increase the speed. Your cooling problem will dissapear after you reach 300 kmh and above...













j/k. Yes it's probably cavitation of the water pump. The remedy is not to change the waterpump, but to get an underdrive pulley for it.

 

At 137 mph the stock water pump is probably cavitating. That is my experience with the stock ones also. They must drive slower in Japan, lol. Water pumps can be better or even worse. One time an old girlfriend had a replacement water pump put on, big mistake. It would start overheating after just a few minutes anything over 110 mph. Change pulleys is a good idea.