Thats why the rads eat themselves away and block up, 5 years is asking for trouble as there are precipitates that slowly block the rad from the bottom up and at the end of the 100,000km you'd be tossing the rad away (Ally one with plastic tanks) because it can't be rodded out without intruducing leaks. 40,000km or 2 years is a good time frame IMO.
JC

