Hi and welcome to the forum. 1st things 1st, if yours is a 98 car it definately IS NOT a 115 Tdi, it will be a 90 or a 110, now we know that if it's a 110, then there's only 5 bhp missing - but the point is they may as well be 2 completely different engines! Tdi 90 & 110 are "traditional" direct injection motors, with diesel injector pump, pipework and injectors all visible when you take the plastic cover off the top of the engine. 115 (and 130) are PD or pumpe deuse engines, with unit injectors, each pressurised by an exhaust lobe on the cam, and the fuel being released into the chamber electrically... So, if the dealer has relied on you telling them it is a 115 - (they really are this thick!) they may have fitted the incorrect parts, as the crank pulleys are different - the 115 & 130 have a timing belt which is 5mm wider to compensate for the extra load.. Or then again thay may simply not have tigtened the retaing bolt....... Mike