Went to the oil change place, took my own filter as I don't trust the generic brand there.

While I saw the guy put in new synthetic oil I counted the bottles he was putting in from behind the safety glass. After the 6th quart I saw him open another one. I thought its ok since my '01 V70 T5 takes 6.1 quarts.

I was amazed to see him drain the 7th ****ing quart in the engine. And convincingly both he and the management said "nooo its 7 quarts, don't worry you're ok" and I know I'm right.

What do I do now?

Drain the whole thing and put new oil in as I know I won't be able to take out the proper amount by taking the plug out and putting it back in at the right time.

How do I go about this?

 

Check oil level first, if it is above max do not drive
When car is cold take the tplug out and drain some oil out. After putting plug back check level using dipstick and add more oil if needed. You can use same oil since it is new. Have some towels handy. Difference from min to max on the dipstick is about 1 quart

 

Taking the oil filter off and draining that is usually good for about 500mls of oil.

Regards, Andrew.