You have Mercury 2003 grand marquis what type of engine coolant to use?
A 2003 Mercury Grand Marquis requires Ford Motorcraft Gold coolant or an equivalent coolant that meets Ford specification WSS-M97B44-D. This is a type of low-silicate, ethylene glycol-based coolant. Do not use just any antifreeze; using the wrong type can damage your engine. Always check your owner's manual for the most precise and up-to-date recommendation.