Hello again- As my wife's 2002 Passat V6 2.8L 4 motion wagon just succumbed to an untimely death due to a SLUDGE problem, I am looking to purchase an Audi A6 wagon to replace the Passat. I've been told that Audi specified synthetic oil for use in their motors sometime around the year 2000, maybe earlier. Hopefully this will all but eliminate the chance of purchasing another sludge bucket. The conventional oil (when not changed) forms a thick almost tar-like substance that covers the oil pump screen, eventually dropping the oil pressure to the point where the cam chain tensioner self destructs. I replaced the tensioner, replaced the oil pump, but unfortunately got there too late. There is still a ticking sound coming from within the motor, probably a connecting rod or main bearing gone bad.The tensioner cost over $600.00, the pump over $300.00, just can't throw anymore money at this motor. Guess I'll just park it and look for a good used motor sometime in the future. Meanwhile, the hunt is on to find a good low mileage A6 wagon. Suggestions??? Thank you, Paul, Providence, RI