Take the 850s to the highway?

Hello, an acquaintance thought it would be useful with my Volvo 850 2.5 10V not only short distance and every day 13 km to go to work and 13 km back (over land), but sometimes with 170 over the track (so 100 km ). And that regularly. We came to it because my engine oil (also after the oil change) is so funny white-smoke on the oil measuring rod. The workshop master says it would be ok and the engine would not pull water and nothing. Maybe it would be on winter operation and on the short work path. Is it really possible that this short work path (constantly speed 90-100 / without traffic lights and crossings) has a bad effect on the engine, the driving performance, the idle????? I actually feel that the car sometimes jerks and swings at slow speed at low to medium speed. Only when you give gas the rocking moose calms down quickly again.# What do you mean? Thank you very much!