I just purchased a used Toyota Avalon with the 3.0 V6 I'm reading a lot of posts on different forms on how these engines are prone to sludge buildup. The vehicle had 20000 miles when I purchased it and no maint records. The oil was honey colored when I had it changed at the Toyota dealer. I've since put a 1000 miles and the oil on the dipstick is clean no discolor that I can tell. Does this indicate that the engine is free of sludge? Any opinions?