Join Date: Mar 2011
Location: Brisbane, Qld, Australia
I would recommend the belt be changed every 100,000Kms.
My lil 00UTY is almost at 400,000Kms now (reading 399,605) and I have religiously had the timing belt changed every 100K - and the engine is fine with no problems thus far.
With regard to the water pump - It finally gave up (the reason I know is that the poor 00UTY built up enough pressure in the coolant to split the top of my radiator!) at just before I had the 300,000K service done.
The guys at Mitsi found that the water pump was wearing out (see above sentence!) and all the timing belt guide rollers needed replacing too as they had worn.
Bear in mind that this 'extra' work was only required at 300,000Kms, so unless your Outty has gone that far everything should be fine.
As long as you are using a mechanic who knows his job, the water pump, pulley rollers, etc should all be inspected anyway whilst he has the front of the engine open for the timing belt change.
Hope this info helps!