Does regular green antifreeze/coolant have a shelf life? Dollar General has regular green Texaco antifreeze/coolant for $5.00 a gallon and I have several $2.00 off coupons on Texaco antifreeze/coolant.
Probably because on paper, they would have to assume responsibility for saying it can last many years after being purchased, should anything go wrong of course. Luckily, in reality, not much degradation is likely to happen to coolant concentrate, sitting harmlessly in its bottle.quote:
Originally posted by Ray H:
(Someone kindly explain to this humble pilgrim [me] why the stuff will last "many years" on a store shelf, but less than one year stored in my garage.)
Just a note, you definitely do NOT want to mix your concentrate with water and then store it. You should only mix it with water right before you are going to add it to your engine.quote:
Originally posted by Cutehumor:
oops, I have 2.5 bottles of peak 50/50 diluted green antifreeze that I got free after rebate from rite aid. it's been sitting for a year now. I guess I won't stock up on anymore antifreeze. I run the green stuff at least 2-3 years
Water destabilizes the chemicals and you are more likely to see precipitation. The formulators can get away with premix because it can be argued that the fallout is negligible. Just a rule of thumb is that a fresh premix is better than one that has been sitting around forever. Trust me on this... I do stability studies a lot.quote:
Originally posted by Ray H:
Really? What does distilled water do to concentrate in a jug that it doesn't do to concentrate in a cooling system? How would 50/50 mix sitting on a shelf at room temperature tank when it is good to go for 4 or 5 years' worth of heat-cool cycles in the radiator? How do the antifreeze formulators get away with marketing pre-mix that's sat on store shelves for who knows how freakin' long?
What about for a top-off? Any risks using some (quite) old conventional coolant concentrate (regular green, ASTM D4985 low-silicate) from a sealed bottle, properly diluted now at the time of use, for topping off? I'm aware that silicates can cause problems (see quote below), but perhaps the pH of coolant concentrate is high enough to mitigate this problem?Does regular green antifreeze/coolant have a shelf life?
Two years is a good general estimate. I wouldn't use anything older than 3 years old for sure though.
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.