You can view the 1999 Mercury Grand Marquis owners manual online at :
www . motorcraft service . com ( no spaces )
Click on Owner Guides
For a 1999 Mercury Grand Marquis : ( the engine air filter is Motorcraft FA-1668 )
You take it to autozone and they will show you
how to take the door panel off of a 1997 mercury marquis
According to the 1996 Mercury Grand Marquis Owner Guide ( 5W-30 is the PREFERRED engine oil )
Dexcool
take it to the dealer
Take it to Best Buy
5
Pentosin Type G12.
According to the 2004 Mercury Grand Marquis Owner Guide : With engine oil filter change : ( 6.0 U.S. quarts of 5W-20 )
Take it to a repair shop.
Remove the transmission and take it off.