I see this problem alot and this is the case. Toyota trucks with V6 suffer from this plague as do VW 1.9 TD I have seen many. The crank bolt is remove to service the timing belt and not properly torqued when reinstalled. In the VW case the bolt should not be removed just the pulley but many technicians assume it does. As Frank pointed out, the customer will often drive the vehicle until it doesn't run then you have to inform them that they have done extensive damage. I have repaired or replaced damaged components and I install thread lock on all, most get a new bolt. Even if I know I will be servicing it again in 100,000km. The biggest problem in retorquing the nut is stopping the engine from rotating and locking the flywheel/ring gear works for me. Good luck <img src="/forums/images/graemlins/cheers.gif" alt="" />