It is important to have the right types of fluids in a car for it to run smoothly. A Grand Marquis will use engine oil 5w-20 or 5w-30.
5w-30 is what I use in my 2000 grand marquis, in 2001 ford started saying 5w-20.
According to the 2000 Mercury Grand Marquis Owner Guide ( 5W-30 ) ( with engine oil filter change , 5.0 U.S. quarts / 4.7 litres of 5W-30 engine oil )
( 5 quarts ) with engine oil filter change ( according to the 1996 Mercury Grand Marquis Owner Guide )
A 1999 Ford Grand Marquis typically requires about 5 quarts of oil when performing an oil change, including the oil filter. It's important to check the owner's manual for the exact specifications, as this can vary slightly depending on the engine type and any specific configurations. Always ensure to use the recommended oil type for optimal performance.
The 2006 Mercury Grand Marquis owners manual shows : The use of synthetic or synthetic blend motor oil is not mandatory - the oil just has to meet Ford specifications
According to the 2001 Mercury Grand Marquis Owner Guide ( 5W-20 ) ( with engine oil filter change , 5.0 U.S. quarts / 4.7 litres of 5W-20 engine oil )
According to the 2003 Mercury Grand Marquis Owner Guide : ( " regular " unleaded gasoline , 87 octane )
10-20 or 10-30 is a good weight
You need to use a Paraffin base viscosity oil like the Motorcraft YN-9........
Was built for R12, should be converted to R134a
According to the 2002 Mercury Grand Marquis Owner Guide : With engine oil filter change : The 4.6 liter V8 engine takes ( 5.0 U.S. quarts of 5W-20 )
As long as the engine is ok you can use: 10W30 10W40 I recommend using Vavoline.