I was buying some windshield washer fluid at Canadian Tire the other day and noticed there were two different types of antifreeze - green and orange.
What's the difference?
First of all, I hope you aren't confusing windshield washer fluid and anti-freeze? They are not interchangeable.
Winter washer fluid is treated to lower the freezing point, but does not have the lubricants and other additives critical to antifreeze. Hopefully, your query was from observation only.
The principal reason for the different anti-freeze colours is that green is commonly used to identify the older type of antifreeze and orange the newer long-life or extended-use antifreeze.
Both use ethylene glycol, which is toxic, for a base so be careful when disposing of it. Every year, we see stories of pets or other animals that have been severely harmed by drinking antifreeze left open or poured out on the ground. The sweat smell/taste is attractive to them.
Both types also use a variety of additives to prevent corrosion, lubricate pumps and seals, etc., as well as provide the critical function of drawing heat created by combustion and circulating through the engine and radiator where it can be extracted.
Before adding or changing antifreeze, check with your owner's manual or the parts counter to make sure you are using the type recommended by the manufacturer. This is critical because of the different metals and surfaces in different engines iron, aluminum, etc.