The owners manuel says the first one is to be done at 50K and every 30K afterwards. I did mine at 30K to be on the safe side and added the waterwetter to keep the temps down and it has worked. My CSVT is "cooler" than any Tour I've seen. Most have the needle straight up in the middle, but mine is way over to the left, like if it were between 1/8-1/4 on the gas gauge. Keeping the coolant fresh keeps the acid levels down which helps that waterpump and we all know it needs all the help it can get
