I have read today by chance in the operating instructions, which must be filled in in the Ka 5w40. So far he has only got 10w40. What do you think of: Shell Helix Plus 5w40 or Liqui Moly Synthoil High Tech 5w40. Both are reasonable from the price and are fully synthetic. He is supposed to get good oil, has got a new nock, does not take oil until now (75,000 km) and that should remain so despite extreme short distance.