What exactly does a sludge kit do?
My son has a 2003 A4 wagon (44k) and the engine was making lots of noise. he is the second owner and has put 10,000 miles on car in approx 1 yr. the diagnostic tests at the dealer were not good. They said that they would first do a sludge kit and if the diagnostics didn't change it could be a bad motor. Apparently the kit worked and the car runs fine. Again, what does the kit do? He had the oil changed twice since he as given the car

Thanks in advance,

Bill
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