Oil consumption over mountain passes.
 

I recently took my V70T AWD (104000 miles) over three consecutive mountain passes in the English Lake District. These were all single track with passing places and very steep, like numerous 1 in 3 sections involving really tight full-lock corners and long 1 in 4s. This was fully laden with 5 adults in thick mist / cloud and the car performed wonderfully. Now going up part of the Hardknots pass we could smell hot oil but the temperature guage stayed at it's usual hot-running level and there was no visible smoke. Later in the day I checked the oil level (5/30 fully synthetic) and it had dropped noticably on the dipstick from the top marker to just above the lower marker wheras normally it doen't use any oil between changes. Does anyone know if this consumption is normal on very steep hills due to engine design or is it due to the loading and power required or has a fault developed? Thanks Michael