What color coolant do i need?

I have a 1998 Ford Windstar. The coolant is so low i can't see what color it is, and i know its bad to mix colors. My dad was the last one to fill it up but hes since passed away so i have no way of knowing what color was put in.
So my question is, how do i know what color to use?
I don't want to have to flush the system but i will if thats the only option.
Please only answer if you know. Please don't guess.

Just go over to the auto parts store and tell 'em what vehicle/year you have -- they'll help you buy the right stuff.

If the coolant is low then the first thing you need to do is find out why it is low. You have a leak somewhere or you have a blown head gasket. You will need green antifreeze/

Just go to Advance Auto and buy their antifreeze that is compatible with all coolants.

Bule

Blue

Double check this, but I think that uses standard coolant, which most people would call "green" coolant.
My suggestion: Top it off with distilled water. You need to do a full flush and not waste money putting another type of coolant in there.
Then within the next few weeks do a full flush. This must be done within a few weeks and BEFORE any temperatures get below freezing. Drain, fill with water, run heater on high, repeat until clean. Drain then top off with 1 gallon of coolant or what ever gets you to about 50/50 mix. Capacity /2 = amount of coolant needed. Top off with distilled water.

The auto parts store can tell you when you go to get the coolant.