Presented By Wessel Grimbeek
You’ve got the hood up for the first under hood check in a while, which isn’t surprising in this era of self-service gas. Checking the coolant level, you see that it’s down. You don’t carry a jug of antifreeze with you, so instead of doing anything, you just worry about it until you get home.
Then, you realize that it’s finally time to change the whole system, not just top up. At least the auto parts store is on the way home, all the better to pick up a couple of jugs of antifreeze. But what kind? The parts store now stocks three colours: yellow, green and orange. Huh? Isn’t all antifreeze green? Isn’t it all the same?
Are all Antifreeze Compatible?
The bad news is that it doesn’t come down to colour matching. Therefore, no. There are a few cases where you can get a fast case of corrosion, some where the water pump can be both eroded and corroded to an early death, and a lot of cases where you can shorten the effective life of the antifreeze. Antifreeze itself (most commonly a chemical called ethylene glycol) doesn’t wear out–ever–but the key ingredients are the rust and corrosion inhibitors, and they get used up. The most common inhibitors, silicates for aluminum protection, are used up faster than others. That’s why some new cars like all General Motors, Mercury Cougar, VW/Audi models have red or orange antifreeze with a new class of inhibitors, called organic acids.
How about just pouring orange antifreeze into every cooling system?
The new organic acid antifreezes may be used only if the cooling system has an aluminium radiator rather than a copper and brass system, therefore no, don’t just pour orange antifreeze into your cooling system. However, let’s assume the reason you’re thinking of a coolant change is because you’re changing a cooling system part (pump, radiator, heater, thermostat housing) on a system with a conventional coolant, not an organic acid orange or pink. In that case, don’t change to organic acid orange, even if the part you’re installing is aluminum. Use a fresh fill of familiar U.S. yellow/gold or green silicated antifreeze. The two orange extended-life antifreezes are compatible with each other, with what’s factory-fill in GM cars and the ’99 Mercury Cougar, and with the pink in VW/Audi cars. However, they’re not compatible with a special orange antifreeze in 1998-99 Chrysler L/H cars (Dodge Intrepid/Chrysler Concorde and 300M), a special “hybrid” mix of organic acids and silicates. The green in most Japanese cars contains no silicates, so it’s not the same as the green in the parts store. The yellow in some European cars contains some silicates, but it’s very different from yellow Prestone, the top-selling U.S. brand. And then there is red antifreeze used by Toyota, and blue used on some European and Korean cars.
What if all you have on hand is regular yellow/gold or green?
Well, if you’re desperate, use what you’ve got, because it’s better than running low on coolant and possibly overheating. But the mixture is shortening the life of the antifreeze. It would take lab tests to tell by how much, so the best deal is to do the equivalent of a “retrofit.” You can’t retrofit all systems neither can you drain green or yellow/gold from the radiator and refilling with orange.
What if the system has Japanese green, Toyota red, Korean or European blue, or European yellow?
As we noted, European and Korean formulas have silicates, so green or yellow/gold is all right, but it slightly compromises the extended life formulas some have. Typically all that means is: Change at 30,000 instead of 36,000 miles. The Japanese green and red antifreezes have no silicates, but they are very different from U.S. orange. If you really drain out the old antifreeze from any of these systems (thoroughly rinse the system with fresh water), you certainly can refill with a yellow/gold or green silicated antifreeze.
