Well, that’s why sometimes you “pay” for a company to realize the shortcomings by halving an interval and enforcing it. Porsche has goofed a few times and one in particular that is known across the world. But they’ve since and prior backed many issues that have arisen whether their fault or not. That 4% (worse case as many are at 2%) retarding is on C30 spec oil. There are many 40 weights far better out there. I never fell into the .8%ash trap as my DPF isn’t worth a motor. On top of that, pre em update used significantly less DPF and EGR which is easier all around. Worth forgoing the nearly $12k they wanted us to take. Funny now the vehicles that haven’t been touched are going for that and more because of how they are (thank you Bosch and Porsche).
Regarding oil, I will have to add about 12 oz every 3-5k depending on how my wife used. T6 which I suspect is evaporated/consumed much like yours. T6 has done that for all the vehicles actually which I didn’t see as a big deal. In addition, I only fill to 3/4 to reduce blowby/wind age.
Didn’t know the 335 used the CP3. I might have to look for one…..that hasn’t had 12-15k intervals. I suspect the fill capacity is 6-8qts?
We’re a family of 1.9l VW’s, and 2.1l Merc Sprinter.
Having a lift pump on the CP4.2 has decreased issues with running on oxygen (the suspected big killer) during a loss of prime.