The filter on a 2008 is a canister type filter, not the common spin on type. It is located on the front of the engine and is accessed through an access plate in the splash shield on the underside of the car just behind the bumper. If you look you will see this marked in raised letter on the access cover.
By the way the oil drain plug is located under another access cover in the same plastic splash shield as the is oil filter canister.
I pretty sure your looking at 5 with the filter.
STP OIL FILTER S3675
Quaker State QS16 Oil Filter
For b18b1 it's next to the oil filter, on the left of the oil filter when sitting in the car
ore83-013
There is a clearly labeled cover over the general area of the oil filter behind the cross member on the underside of the car.
According to the 2006 Mercury Milan Owner Guide : For the 3.0 litre " Duratec " V6 engine : With engine oil filter change : ( 6.0 US. quarts / 5.7 litres of 5W-20 )
The Oil is drained by removing a plug in the oil pan, and letting it run into a pan. The filter is screwed to the side of the engine. After the oil is drained and the filter changed, add oil and check frequently to prevent overfilling.
4.5 quarts ( 4.25 liters ) with engine oil filter change , according to the Owner Guide
4.5 quarts / 4.25 liters , with engine oil filter change ( according to the Owner Guide )
( 6.0 quarts ) with engine oil filter change , according to the Owner Guide
According to the ( 2006 ) Mercury Milan Owner Guide : With engine oil filter change : The 3.0 liter Duratec , V6 engine takes : ( 5.7 liters / 6.0 U.S. quarts of 5W-20 )
Place a drip pan below the oil pan and oil filter. Remove the oil pan plug. Drain the oil into the oil pan. Replace the plug to the oil pan. Turn the oil filter to the left, to remove. Fill the oil filter with oil and replace it to its original position. Fill the motor with oil.
Just a socket wrench that will fit on the lid for the filter because it is a an actual filter cannister not the usual steel filter
I do not know about the conversion but it is 4 quarts with the filter changed also.
You acces the oil filter on the 4cylinder engine through the passenger side front wheel well. There should be an acess area for you to go through.
Bottom of the engine on the oil pan.