Q: Mixing red and green coolant in the radiator

asked by on

What happens if you mix red and green coolant in the radiator? By the way, it's a 1998 Iswara.

Realize that green antifreeze is the old style antifreeze. That was an old type of antifreeze where the glycol lasts maybe three years max. So you’ve got to change the coolant maybe three years or every 15,000 miles. The modern coolant comes in various different colors and red happens to be one of them. It often can last five years or 150,000 miles. So it’s a better antifreeze to use.

Now, if you mix them--they are not supposed to be mixed--but if you mix them it’s not like mixing an acid and a base and you are not going to have and explosion or anything like that. It’s just that, when you do mix them, then when you use any of the machines that mechanics use to see what the freeze point is, you’re going to get inaccurate readings. So if somebody tries to check to see if you have enough antifreeze in your system, so it won’t freeze in the winter for example, your reading might be wrong. If it gets really cold, you might end up cracking your engine. So basically, you’d want to stick to the coolant that the car was made for. If you have an older car, say that came with green coolant, you can flush it all out and put the newer style coolant in and then change it every five years or 150,000 miles. It’s perfectly backwards compatible if you want to do that. But you really don’t want to mix them, it’s not that good of an idea to mix them. If you want to have the correct coolant added for you, consider YourMechanic. They will be able to come to your home or office to perform this service.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Mixing red and green coolant in the radiator

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Coolant leak

Hello. You will probably need a mechanic to perform an inspection on the cooling system. The mechanic can pressurize the cooling system with the car cold and locate the leak. There are multiple places for a leak to happen, such...

Q: Q: My coolant reservoir is empty and coolant is splattered over my engine

Driving a car with "zero" coolant will destroy the engine within minutes. Even after a coolant leak, though, you have some coolant in the engine and water can sometimes be added to enable one to drive a "short" distance as...

Q: Q: Antifreeze leak

An antifreeze leak may not affect the level in the overflow bottle. The leak may be the heater core or radiator leaking; a pressure test is typically used to locate the leak. I recommend having a mechanic, such as one...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...