German dealers use 5-30 Castrol synthetic. Thats all you need. The oil change interval here is 15,000km's as well. A good synthetic will last. My last Blackstone around 7500+miles was to got to 10,000mi which is about what my German dealer recommends. Go figure.
My car gets driven hard but responsibly. I have an oil cooler and cover plate for the cooler winter months. I see normally 185+ on temps but nothing over 220+ in summer and hard, fun driving.
Bvl has great advice for you above. Do not over think this issue. Its soooooo not worth it.
|