2000 Audi A6 4.2L V8 quattro engine cooling system failure. The plastic coolant pipe between the oil cooler housing and the engine block fails causing potential catastrophic coolant loss, overheated engine and potential fire. The plastic pipe hardens/crumbles with age, approximately 10 years and 135K miles. I replaced the pipe...it takes about 10 manhours. The replacement Audi part is maybe $20 but it is still plastic. I replaced it with a billet aluminum part with double O-rings. Dealer wanted $2900 to repair!! I understand this part is on every 4.2L V8 on both A6 and A8 cars from 1998 to current 2010.

- Silver Spring, MD, USA

A strange noise from the engine compartment of a 2000 A6 Audi began several months ago. The noise became progressively louder. I then suspected a water pump malfunction was forthcoming. The vehicle was taken to an Audi dealer for evaluation. They determined that the water pump was defective, and recommended a replacement. Most people would not have recognized this noise and an on road accident could have taken place on a freeway when the engine would have overheated and seized. Since there was only 31500 miles on the vehicle I am concerned that this type of problem occurred at all. Either the pump shaft was bent by an over tightened belt or the part was defective at manufacturing point. (the belt has never been adjusted after purchase).

- Akron, OH, USA

Near total loss of power (intermittent) 17 error codes in obd. New triptonic transmission 1 month after expiration of warentee. Extended warentee never offered by Audi. Error codes include throttle housing and cam error. I have spent nearly $7,000 in 10 monthes on mechanical repairs and mechanic says that I need approximatly $6,300 more. Audi said that I can have the dealer run a dignostic at my own expense. Addition to the $6,300 need. Check engine light has constantly come on since purchase. Dealer siad that he advises customer many times to disconnect light. Constant repairs since ownership. Audi is not helpfull.

- La Mirada, CA, USA