My 12-yr old Honda car is in good condition, and I use the green ethylene glycol coolant in it. I don't drive it much, maybe I put less than 5000 miles yearly on it. I used to change the coolant (after 3 drains and refills with distilled water) every 18 months. Now I'm thinking maybe every 3 or 4 years because of the low mileage I clock up. Yesterday I measured the voltage in the coolant with respect to ground, and it was 0.15 volt. Coolant was 18 months old. Battery was not disconnected during the test. Comments?
Time-based or Mileage-based coolant change ?
- Thread starter berniedd
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I believe your plan is good
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It's a galvanic thing. But to tie it into your specific grav ..how can one check the charge on a battery? SG??
While I never bothered to research it, my observations/reasoning/opinions are that coolant longevity is tied to the heating/cooling cycles it sees. There should be xx amount of chemical reaction with each introduction of thermal energy to sustain the reactions. Fewer transitions per mile ..more miles. Fewer transition per year ..more years. I'm sure that there are other aspects/nuances/effects ..but they probably are subordinate to that fundamental degradation component.
While I never bothered to research it, my observations/reasoning/opinions are that coolant longevity is tied to the heating/cooling cycles it sees. There should be xx amount of chemical reaction with each introduction of thermal energy to sustain the reactions. Fewer transitions per mile ..more miles. Fewer transition per year ..more years. I'm sure that there are other aspects/nuances/effects ..but they probably are subordinate to that fundamental degradation component.
Kestas
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Way back when I've seen Ford's data on metal protection for the old silicated formulas during accelerated tests. What struck me was how the coolant predictably lost its protection at 30K... not 25K, or 35K, but right at 30K!
I can't comment on "decelerated" tests such as berniedd's, though I do extend the drain and refill on my classic car to four years. It sees little mileage.
I can't comment on "decelerated" tests such as berniedd's, though I do extend the drain and refill on my classic car to four years. It sees little mileage.
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I guess they dialed it in rather well. As I said, my belief is just that, my own self constructed mythos
Originally Posted By: berniedd
I measured the voltage in the coolant with respect to ground, and it was 0.15 volt. Comments?
that is a good reading as long as the coolant reads .5 volts or below.
was the headlights on during the test?
also: testing voltage on antifreeze has been common in the diesel industry for years. don't want electrolysis to set in and eat the piston liners! mike
I measured the voltage in the coolant with respect to ground, and it was 0.15 volt. Comments?
that is a good reading as long as the coolant reads .5 volts or below.
was the headlights on during the test?
also: testing voltage on antifreeze has been common in the diesel industry for years. don't want electrolysis to set in and eat the piston liners! mike
No, all lights, engine, radio etc were off. Looks like I'm good for 2 years more.
Originally Posted By: berniedd
My 12-yr old Honda car is in good condition, and I use the green ethylene glycol coolant in it. I don't drive it much, maybe I put less than 5000 miles yearly on it. I used to change the coolant (after 3 drains and refills with distilled water) every 18 months. Now I'm thinking maybe every 3 or 4 years because of the low mileage I clock up. Yesterday I measured the voltage in the coolant with respect to ground, and it was 0.15 volt. Coolant was 18 months old. Battery was not disconnected during the test. Comments?
The cooling system is one place where time probably matters way more than mileage. The reactions that cause corrosion, deplete antifreeze additives, and cause additives to precipitate out as grit go on whether or not the engine is running. The reaction rate may be slightly different when the engine is hot and running vs cold and the coolant is sitting still, but only by a little bit. Go by the calendar for coolant.
I don't think the conductivity test gives a complete picture, either. IT can tell you in general if the coolant is protecting, but what it can't do is tell you if ALL the components are still OK. Coolants have chemicals to protect primarily iron, others to protect primarily aluminum, some for brass/bronze, etc. A simple bulk conductivity test isn't going to tell you if the additives are all depleting together or if one is getting used up faster than the others.
My 12-yr old Honda car is in good condition, and I use the green ethylene glycol coolant in it. I don't drive it much, maybe I put less than 5000 miles yearly on it. I used to change the coolant (after 3 drains and refills with distilled water) every 18 months. Now I'm thinking maybe every 3 or 4 years because of the low mileage I clock up. Yesterday I measured the voltage in the coolant with respect to ground, and it was 0.15 volt. Coolant was 18 months old. Battery was not disconnected during the test. Comments?
The cooling system is one place where time probably matters way more than mileage. The reactions that cause corrosion, deplete antifreeze additives, and cause additives to precipitate out as grit go on whether or not the engine is running. The reaction rate may be slightly different when the engine is hot and running vs cold and the coolant is sitting still, but only by a little bit. Go by the calendar for coolant.
I don't think the conductivity test gives a complete picture, either. IT can tell you in general if the coolant is protecting, but what it can't do is tell you if ALL the components are still OK. Coolants have chemicals to protect primarily iron, others to protect primarily aluminum, some for brass/bronze, etc. A simple bulk conductivity test isn't going to tell you if the additives are all depleting together or if one is getting used up faster than the others.
I agree. While I think you could go 3-4 years with the original green formula, anything over 2 years is pushing it if you want to keep your cooling system in best shape. I like the Green but you will have nasty damage if it isn't changed regularly around 2 years. Sometimes it's not always obvious that the coolant is depleted and by the time it is, there probably is corrosion and pitting.
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