I had to have my engine replaced on my 2003 Passat due to a known oil sludge defect. Thankfully, it was covered under a special extended warranty. The problem is that after replacement and on the same day I picked up the car, the engine light went on. I brought it back to the dealer and found out that the turbo had failed but it WASN'T due to the oil sludge engine problem. At the time, I was ignorant about how the turbo worked and in order to get my car fixed authorized a $1500 repair. I'venow come to find out that the oil is the key to maintaining the turbo. Does anyone know if it ispossible thatan oil sludge problem resulting in an engine replacement could have nothing to do with a turbo failure?? I am being told by VW that it was just a coincidence that the turbo failed the same day I got my car back after the engine was replaced. They refuse to reimburse any part of the expense.Please advise.