as above , i don't know how this has happened, i normally take very good care of my car servicing every 6000 miles. since i started hearing the tapping sound from the engine, i checked my dipstick and couldn't see any oil and it took it 1.5 litres of oil to bring it back to full. how it went down to 3 liters i cannot understand. the tapping sound is still there though. i wil take it for an oil and filter change tommorow. could the oil pump has packed up?

 

It could be a number of things, have a good listen under the bonnet to try and find which part of the engine its coming from, if you got a loud exhaust & induction system it makes it harder to find tho, I found that out.
My last scoob used to get through some oil & it only had the lightest smoke mist from the exhaust on hard accel, couldnt see it myself, only knew this from someone following me.

 

i tend not to look behind me when nailing it too lol

 

I'd also check things like your sump plug tightness and oil filter (aftermarket oil filters can be crap on scoobs - they work loose!).

Give her an oil change, then monitor the levels at regular intervals to see how much is being used.

 

what is a sump plug? is it the screw we undo to empty the oil at the bottom of the engine? i have only used oem subaru filters as long as oil and fuel filters go. will double check though. thanx for the help