As I understand, there appears to be advantages (such as reduction in wear) in using, for example; Mobil 1 Turbo Diesel Truck 5w40 in my Passat 2004 TDI that 'requires' 505.01 or
507. As my Passat is out of the warranty period, I have been considering switching to a CJ-4 oil (like the above). Do we have an understanding as to what the negatives may be? the effects on EGR, exhaust system, etc?...