old coolant

[tarbasd]

Hi,

I have about two quarts of old coolant, but not used. It is about 3 years old and it was in my closet all the time. It is in a 1 gallon container, which was opened 3 years ago, half of the coolant was used, the other half wasn't. No I'm thinking of a coolant flush. I understand it is safe to mix different brands of ethylene-glycol based coolants, but do you think I can use this old coolant? Does it get "spoiled" just by sitting in the closet and not in the cooling system?

Thanks,

[touringcamry]

I got this from Prestone's web site:

Q. What is the shelf life of Prestone® Antifreeze/Coolant?
A. If the product is still in the original sealed container then it has a shelf life of many years. If the product has been opened and has not been diluted with water then it also has a shelf life of many years.

Also found this about Havoline coolant:

The primary limiting factor in the shelf life of a coolant is silicate instability. Since silicate will
eventually polymerize to silicate gel, all traditional coolants have a shelf life of about 18 months.
Havoline Extended Life Anti-Freeze/Coolant DEX-COOL®
is silicate-free and, therefore, can be
stored for at least 8 years without a problem provided the integrity of the container is maintained.

[tarbasd]

Thanks! It looks like I better dispose it. Even the "many years" is expiring.