Your 1999 F53 Owners Manual says this: Adding engine coolant
Use only Ford Premium Engine Coolant E2FZ-19549–AA (in Oregon, F5FZ-19549–CC, in Canada, Motorcraft CXC-10) or a premium engine coolant that meets Ford specification ESE-M97B44–A.
• DO NOT USE Ford Extended Life Engine Coolant F6AZ-19544–AA (orange in color).
• DO NOT USE a DEX-COOL engine coolant or an equivalent engine coolant that meets Ford specification WSS-M97B44–D.
• DO NOT USE alcohol or methanol antifreeze or any engine coolants mixed with alcohol or methanol antifreeze.
• DO NOT USE supplemental coolant additives in your vehicle. These additives may harm your engine’s cooling system.
• DO NOT MIX recycled coolant and conventional coolant together in your vehicle. Mixing of engine coolants may harm
your engine’s cooling system.
• The use of an improper coolant may harm engine and cooling system components and may void the warranty of your vehicle’s engine cooling system.
• Use only the type of coolant with which your vehicle was originally equipped. If you are unsure which type of coolant your vehicle requires, contact your local dealer.
Ford didn't use the "orange" coolant until 2015 in the F53. And they used "gold" 2002-2014.
__________________ 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member,FMCA. "We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert the Constitution." Abraham Lincoln