I would suggest that his advice was entirely reasonable provided all of the idlers and water pump (if belt driven) are changed at the same time. The idler bearings will not be fully servicable after 12 years of operation.

PSA belt drives are generally well engineered with reasonably large wheels (crank 21 teeth), wide belts, favourable wrap angles and - importantly, the water pump driven on the slack side of the belt. The other obvious measure they take is to ensure that the number of teeth on the belt is not exactly divisible by the number of teeth on the crank wheel. This spreads the highest tooth loads over the length of the belt as the engine runs, rather than subjecting the same few teeth to high loadings at all times.

VAG would do well to learn from these observations - in particular, a water pump driven from the tight side of a PD belt is, in my view, unwise engineering practice and places the engine at unreasonable risk. My VAG diesel has 20 teeth on the crank wheel and 120 on the belt - stupid.

There is enough evidence now to indicate that the weakness with any well designed belt drive lies in the idlers/tensioner/water pump and not the in belt itself. These components all have grease lubricated rolling bearings which run very hot (bolted to the engine block or head) and eventually the oil component of the grease will run out.

Ford and Honda are fitting oil lubricated belts which will obviously allow the rollers to be oil lubricated (no internal oil seals required). If propely detailed, this will probably represent the optimum solution to a "lifetime belt" engine at minmal cost.

659.