2.0 TDI 140 PS BJ. 2005 – Questions

Hello everyone, drive a SEAT Altea 2.0 TDI 140 HP BJ. 2005 The car has 93 tkm on the tacho and is so good except for a defective cooler and a defective starter freewheel. However, the reports about perishing oil pumps, broken engine suspensions, codified PD elements and torn cylinder head seals/cylinder heads worry me so far. Are there symptoms for errors? Start difficulties: Sometimes it comes a bit sluggish lately – i.e. it sometimes takes 1-2-3 seconds until it starts. In case of load changes on the AB, the rear man sees a distinct Russian flag. A loud bang when I drove out of the underground garage a few days ago – what could that have been? He has not seen the workshop for cost reasons longer time (except for the oil changes that I have done in turn). What can I do (if necessary) to get ahead of the tooth of time (and possibly expensive consequential damage)?