I am thinking of renewing the timing belt on my Golf 4 1.9TDI ASZ, 96kW (PD), 2002, as it nears 90,000km.

I have some questions:

i) I understand that the tensioner should be replaced at the same time, but should the water pump also be replaced?

ii) The manual that I have describes fixing the camshaft in position (using a special tool), removing the sprocket on the camshaft, re-fitting it (upon fitting the new timing belt) and re-torquing it. I do not really understand this. The camshaft is keyed so what is the point of removing it and fitting it back on. Is this really necessary?

iii) My manual also describes fixing the fuel pump sprocket in the correct position (using a special tool) slackening 3 radial bolts on the fuel pump sprocket but not the main central bolt then re-tightening the 3 radial bolts (upon fitting the new timing belt) to a pre-torque, taking the car to a VW dealer (the engine can run with the 3 bolts at their pre-torque), having them check the timing electronically and finally tightening the three bolts after that. Is this also really necessary? Can one not just leave the 3 bolts and fuel pump sprocket un-touched and also not bother with the electronic timing check at VW?

Or am I right in thinking that my manual does not cover the TDI PD (ASZ) engine fully and that the timing belt renewal procedure on the PD engines differs to that on non-PD engines?

Any advice on DIY timing belt replacement on VW TDI PD engines would be much appreciated.

Many thanks in advance,


Jonathan Butler