Alrighty, made a small trip today and the car started heavily smoking blueish smoke while driving. I didn't boost at all and the engine was preheated for 2hours as it's -15 c here. I stopped the car and checked the bay to find out that the alternator belt and a/c belt were very oily and there was also oil dripping down to the ground near crank pulley. I went to grocery store and came back after 20 min and leak was stopped, maybe 0.5 desiliters came out? I restarted the car and it was fine. Didn't smoke and oil pressure was good, but after driving a kilometer it started smoking again. So, the headgasket is the only thing explaining both the leak and smoke, but is it a common that the headgasket causes oil to burn, but won't use water? Valve stem seals and turbo would cause smoke, but these won't leak from the point it leaked today, so maybe there are two different problems?