If the timing belt was to break on the Daihatsu Hijet engine there is a chance that one or more engine valves could bend. It is a good idea to change the timing belt and tensioner if you do not know if the previous owner had done so. It is low cost insurance and preventative maintanence for the engine of your Daihatsu Hijet mini truck to change the timing belt and tensioner. The rubber goes hard over time and starts to crack. The timing belt becomes harder and can break at any time with age. Changing the timing belt and tensioner is a must if you need a water pump replacement.