5w-30 would work best. If you prefer a heavier oil, you could also use 10w-30.
According to the 1997 Mercury Mountaineer Owner Guide : The 5.0 liter V8 engine takes the ( Motorcraft FL-1A ) engine oil filter
Bottom of the engine block.
Not usually
5 US Quarts
On a 1997 Mercury Mountaineer : ( 5W-30 ) for the 5.0 liter / 302 cubic inch V8 ( with filter change , 5.0 U.S. quarts / 4.7 litres of engine oil ) According to the Owner Guide
No,a transmission on a 2005 mercury mountaineer will not fit on a 2000 mercury mountaineer unless you change the oil message on the mountaineer.
On a 1997 Mercury Mountaineer : The engine oil filler tube for the 5.0 litre / 302 cubic inch V8 engine is on the valve cover of the engine , on the right side ( passenger side ) near the front of the valve cover
The only engine available in the 1997 Mercury Mountaineer was the 5.0 liter ( 302 cubic inch ) V8 and with engine oil filter change it took ( 5 quarts / 4.7 liters of engine oil )
The 2000 Mercury Mountaineer owners manual shows ( 5 W 30 ) - for the 4.0 L - SOHC - V6 engine and the 5.0 L - V8 engine
5W-30 , is the preferred oil for the 4.0 liter V6 , according to the Owner Guide
The check " gage " light on in your 1997 Mercury Mountaineer indicates that either your engine oil pressure is LOW , your engine temperature is HIGH or your gas tank is AT OR NEAR EMPTY .
5 quarts ( 4.7 liters ) with engine oil filter change