Mopar 10 year/150K mile premix coolant shelf life in opened container

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Aug 9, 2022
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Hello all,

I recently flushed the coolant in my 2015 Jeep Wrangler at the same time as a thermostat replacement using the Mopar OAT 10 year/150K mile concentrate coolant. I ended up short on the quantity of new coolant I purchased for the flush, so I had to additionally use 1 gallon of coolant I purchased 4 years ago on 8/24/2018 for topping off my overflow tank. The 4 year old coolant is the Mopar 10 year/150K mile prediluted 50:50 premix with a manufacturing date of 3/17/2018, and had been sitting on the shelf in my store room in the original opened but tightly capped container. I have read various older threads where people stated that opened prediluted coolant has a shorter shelf life than concentrate, with varying figures from 1 year to 5 years with reduced corrosion protection. How long will I have full protection before needing to replace this coolant again?
 
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explorer2030

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The coolant is good for 10 years from the time your install it, not from the date it's manufactured.
Are you saying there is essentially unlimited shelf life on opened but unused coolant? My understanding was that additives drop out after a certain period of time and corrosion protection is reduced.
 
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explorer2030

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My inclination was to change it again before 6 years so that the total age of the coolant wouldn't exceed 10 years, but you don't see any issue with leaving it in for a full 10 years?
 
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If you feel better changing it sooner, go ahead. Either is fine, but 6 years is way down the road to worry about now. It could get stolen or wrecked well before that or maybe you see something you wan't something different in a few years.
 
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Not an issue, coolant doesn’t have shelf life.
Having said that, I have never taken any of these coolants to their full change interval. I just can’t bring myself to leave it alone for that long. Especially since radiator drain and fill is so easy to do.
I've always wondered about this. I know with oils, you pretty much can't trust the manufacturer recommended intervals anymore these days. 10 years for the initial change seems like a really long time for coolant, would be curious if there's any scientific basis behind that.
 
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I’ve always had the inclination to change coolant a little early as well. I did a radiator drain and fill with Honda 50:50 on my 17 accord last year around the 50K mile mark.
Could be wasting money but I figure fresh fluid, fresh additives and that’s what I like to do
 
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If you pull up the manufacturer spec sheet for almost any coolant, it will tell you what they consider the shelf life to be. That said, I wouldn't worry too much about it if I exceeded that, although I'd shake it up well before installing it.
 
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