Coolant change time or mileage

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5,988
Location
Houston, Texas
Thread starter
I don't reach the 100,000 mile mark before 5 years. Is the pink mopar HOAT coolant done after 5 years? I changed it initially around 5 years and like 83,000 miles. I'm at 10 years and 123,000 now.
 
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206
Location
NY
Generally long life coolant is good for 5 years. I figure coolant is more sensitive to time than miles per se.
 
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2,746
Location
San Antonio, TX
I changed the factory fill orange G05 HOAT in my 2012 Ram last year when I hit the 5 year mark. I had 46K miles on the truck at that time. I want this truck to last and the price of Zerex G05 at AAP after discount code (when not on some lousy $2 off a gallon sale) isn't prohibitive IMO. I did not do any analysis on my used coolant. I found the Mopar HOAT MS-9769 pricing to be significantly higher than Zerex G05 so I went with Zerex. It's a light gold / yellow dyed coolant but also MS-9769. Personally I think hot weather driving in Texas beats up coolant chemistry worse / faster than cold weather driving in more northern climates. The good old Arrehnius equation.
 
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1,441
Location
CA
Valvoline told me the life of coolant in the bottle is also 5 years. It's a good idea to check the date code through your smartphone when picking up coolant in store.
 
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921
Location
D/FW Metroplex
Originally Posted By: motor_oil_madman
I don't reach the 100,000 mile mark before 5 years. Is the pink mopar HOAT coolant done after 5 years? I changed it initially around 5 years and like 83,000 miles. I'm at 10 years and 123,000 now.
IMO it is best to treat the coolant life expectancy claims like the manufacturers treat their new car warranties - xx miles/x years, whichever comes first. So if the coolant sees its 5th birthday before it sees its 100,000th mile, change it. Allowing it to go beyond 5 years in order to reach the 100K mile mark is a recipe for disaster IMO, especially considering the severe operating environment your geographical location imposes. (My position on this subject was recently bolstered by personal experience with factory fill Mopar HOAT coolant that was allowed to go beyond the 5 year mark even though it had not yet been in service 100K miles. There were clumps of brown goo left behind in the overflow tank and what looked like sand particles filtered out of the drained coolant when transferring from drain pan to collection jug.)
 
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N.A.
Don't forget that coolant also lubricates the Water Pump etc. So the additives need to be replenished, etc. I agree about the heat being detrimental!
 
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7,841
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Champlain/Hudson Valley
To Onetor and others: I also believed in lubricating the water pump's bearings as an obvious necessity but was told the designs of modern water pumps is such that the bearings are isolated and coolant (or any lube you put into coolant) never touches them. Lubricating them is impossible, they implied. I grew up adding water pump lube to anything which had one.......I wonder if both old and new designs exist.
 
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14,737
Location
Upper Midwest
Originally Posted by Onetor
Don't forget that coolant also lubricates the Water Pump etc. So the additives need to be replenished, etc. I agree about the heat being detrimental!
Which parts are lubricated by the coolant? The water pump bearings are actually protected from the coolant by seals. Once the seal deteriorates and is breached by the coolant the bearings will destruct in short order.
 
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4,220
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Parts Unknown
Originally Posted by kschachn
Originally Posted by Onetor
Don't forget that coolant also lubricates the Water Pump etc. So the additives need to be replenished, etc. I agree about the heat being detrimental!
Which parts are lubricated by the coolant? The water pump bearings are actually protected from the coolant by seals. Once the seal deteriorates and is breached by the coolant the bearings will destruct in short order.
Correct. The pump bearings are behind a seal.
 
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19,679
Location
Sunny Florida
Wait till you get some of that lubricating coolant on any accessory drives like we have in our service vans. If the tensioners and/or idlers get any real penetration by the coolant it's time for replacement in short order.
 
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948
Location
N.A.
Originally Posted by kschachn
Originally Posted by Onetor
Don't forget that coolant also lubricates the Water Pump etc. So the additives need to be replenished, etc. I agree about the heat being detrimental!
Which parts are lubricated by the coolant? The water pump bearings are actually protected from the coolant by seals. Once the seal deteriorates and is breached by the coolant the bearings will destruct in short order.
I stand corrected. Ty
 
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25,022
Location
ON, Canada eh?
I do radiator spill/fill's at 1/2 the allowable intervals that way the coolant in the system is always fresh all the time and there is no need for flush/fill. I have driven all my vehicles to their junk points with original water pumps and radiators.
 
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3,406
Location
FL
I just went 6 yrs on my nissan with 75k miles....makes me feel bad I waited a yr too long,
 
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34,441
Location
NY
I go by time for the coolant. I'd never hit the mileage stated in the owners manual vs. the time in use for the coolant.
 
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189
Location
Monroe, WA
There are two concerns, coolant degradation as it acidifies with age, and inhibitor package depletion. You can check how the glycol is aging with a pH meter (strips won't give you enough resolution). You should make sure your pH meter is calibrated against pH buffer standards because the probes quickly drift out of calibration, especially when they are not stored correctly. The pH should be around 8.0 in a healthy glycol solution for automotive use. And yes.... it ages quicker with heat. The degradation is a chemical reaction and ethylene glycol primarily degrades into glycolic acid (some oxalic, some formic) and all chemical reactions proceed quicker with energy input. Thus ethylene degrades into the acids quicker at higher temps than it would at lower. I've also seen studies that show inhibitor degradation over time. The azoles, in particular, drop with time. I'm not sure of the mechanism whether it is bonded to copper/brass as the inhibiting layer or if it is lost in the non-sealed system. Either way, you could just start at a higher level. The assumption is that it will be run at 50/50 so run it at 65/35 so you have more to start with. It is so cheap to dump it on a regular basis that I err on the side of caution.
 
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