Can you mix orange and yellow coolant?
Yellow coolants are also known as "Global" coolants. They are long-life coolant formulas designed to safely mix with ANY (and I do mean ANY, to all you nutcase Euro car owners out there) colour of antifreeze. They are good for all makes and models of cars and light trucks. This means that yes, they can be mixed with GM Dex-Cool (red/orange) and Chrysler/Ford/Mazda GO-5 (orange) with no danger whatsoever. They can be mixed with Toyota Blue, Volkswagen/Audi/Porsche Pink and Purple coolants as well. If you have a car or light truck, it can take Yellow coolant with no problems. If you have a heavy-duty Diesel truck, it can take Yellow to top up, but heavy-duty red Diesel Antifreeze should be used primarily.
There is Volvo branded coolant that you can buy from the dealership. But that is only branded from another manufacturer. This coolant is orange/yellow. Some say to stay away from green coolant for Volvo's. Others have had good experience with them. But the most important thing is to NOT mix orange AND green coolant. Also mix with distilled water if not already pre-mixed 50/50.
Your coolant is orange because the manufacture added orange dye to the coolant so it is easily recognized. Orange coolant is Organic Acid Technology (OAT) coolant and should not be mixed with Green coolant which is Inorganic Additive Technology (IAT) coolant. Yellow coolant is Hybrid Organic Acid Technology (HOAT) coolant. IAT must be changed about every 2 years, but OAT and HOAT will last 10 years or 100,000 miles. Never mix these coolants together.