Shelf life of Prestone Longlife coolant

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Sep 13, 2003
Waterloo, ON
I don't know much about types of coolants, but I have been looking at the ongoing Dexcool debate. I have a jug of pink Prestone longlife that I bought 11 years ago. (this would have been the first LL coolant from Prestone Jug says "compatible with the extended life coolants used by all new car makers including GM DEX-COOL"

I am looking to change the original coolant in my 1999 Grand Am 2.4. Is this coolant still OK to use? GM says 5 years for the life of installed coolant, but this is still in the jug. Is this stuff the same as DEX-COOL?
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i wouldnt use dex cool, too many horror stories...myself i would run DISTILLED WATEr thru engine for 5 minutes then just use regular 50/50 antifreeze if you are unsure of old prestone
If it was sitting for eleven years I wouldn't use it. the glycol will last forever (not used) but the inhibitors will deplete (yes even on the shelf especially for that long and if it was opened even shorter).

Dex-Cool is fine to use.
That goes for any antifreeze (as far as shelf life).

I would not use conventional green antifreeze as the high silicate content can shorten the water pump seal life.
I just checked their web site and found this in the FAQ section:

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.

Not sure whay "many years" means. I think I will call them...
Here is the reply from Prestone:

Thank you for contacting Prestone,

A Prestone Extended Life Antifreeze/Coolant is good for five years or 150,000 miles which ever is earlier, hence we would recommend you to not to use the product as it is very old and to dispose it as per the Federal/State laws of your region.

Yes, it is safe to use The Prestone Dex-Cool Extended Life Antifreeze/Coolant in a 1999 GM car, however factory fill Dex-Cool that comes in GM vehicles is not a Prestone product and we would recommend you to contact the manufacturer.
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