The coolant levels in my 2006 Subaru Forester seemed low so I was going to pick up Prestone pre-mix from the store and top it off.

The coolant in my car is blue. The manual says SUBARU coolant or an equivalent: a mixture of 50% soft water and 50% ethylene-glycol basis coolant.

The Prestone package says compatible with all cars.

  1. Does that mean the regular Prestone coolant is fine to mix in with the blue coolant that's in there already?
  2. Is Prestone really compatible with ALL cars?
  • Comment because I can't actually answer your question, but Subaru coolant concentrate + some distilled water from your local grocery store is cheap enough that I don't think it's even worth risking using generic coolants.
    – Shamtam
    Sep 27, 2016 at 21:28

1 Answer 1


Color is irrelevant.

For your car, use Subaru Long Life Coolant (comes in 1gallon bottles, and is diluted 50/50). You'll need - at most - just over 7 quarts.

You'll also need the Subaru Coolant Conditioner - it's a tiny bottle, about $3, but essential.

Drain all your old coolant - the Subaru Long Life Coolant is not compatible with anything else (regardless of color). Get as much out as possible, then refill with the Subaru Coolant. Make sure the conditioner gets in there also (quick fact... it's actually a British product called 'Radweld', and it's designed to stop small radiator leaks).

As you have the system drained anyway, consider throwing a new thermostat in there also. Use only the Subaru OEM one, and you'll be good for a long time.

  • are the colors just a dye? because I remember seeing in a car that it said "do not use green coolant" or something like that
    – method
    Oct 28, 2016 at 15:46
  • 2
    It used to be, years ago, that the color of the antifreeze was an indicator of the chemicals that made it up - so if it was dyed orange, you shouldn't use it in cars with an aluminum radiator, for example, because of the acids in it - yellow or green was preferred. Nowadays, it's not so easy - you need to read the ingredients list, or buy the coolant specific for your car. Coolant (usually) lasts so long - 150,000miles - that I suggest buying it from the dealer.
    – PeteCon
    Oct 28, 2016 at 16:10

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .