Fox Is it time to replace the coolant?

PonyGTrider

5 Year Member
Feb 27, 2019
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Hi all,
By accident I tasted a bit of coolant from my 306 engine and it was extremely acidic.
Reading around I found articles about testing the coolant condition using a DVM. I followed the instructions turning the volt meter on to VDC placing the red lead into the coolant in the radiator and the black lead to a good ground. I got a reading of -0.200 Volts but the minus indicates me it is inverted polarity. I then exchanged the leads and then I got the correct 0.200 Volts the articles said you should have 0.400 V or less to be good.

I google this anomaly and the suggestion I received was that my coolant has to be replaced as soon as possible.
I have an aluminum Griffin radiator and a magnesium sacrificial rod hanging inside the rad cap.
Can anyone share an opinion on this one?
I will certainly appreciate it
 
How long has the coolant been in there?

What type of coolant did you use (classic green)?

I have always used these things:

1758045583638.webp
1758045602414.webp


But I hear rumor that these are better? :shrug:

 
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How long has the coolant been in there?

What type of coolant did you use (classic green)?

I have always used these things:

1758045583638.webp
1758045602414.webp


But I hear rumor that these are better? :shrug:

Actually my coolant is old, I use the typical Preston green at 32% concentration. Never had any overheating problems.
Now that you mentioned it I have the second coolant tester you posted I will use it right now.

Thanks for your ideas
When in doubt , Drain it out.
Use distilled water to mix with coolant.
How long has the coolant been in there?

What type of coolant did you use (classic green)?

I have always used these things:

1758045583638.webp
1758045602414.webp


But I hear rumor that these are better? :shrug:

I just used the coolant tester and either it is not good or something else is gong on.
Thanks second photo shows what the coolant in the engine looks like and apparently it is shot. But, the first photo shows what a brand new coolant out of the bottle 50/50 looks like… it reads the same! So is my tester bad or what is going on???
 

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I have always bought full strength coolant and a gallon of distilled water, mixed 50/50 and call it a day.
This has gotten me 316,000 miles on my stang, so ill stick with what has been working.
I’ve always used Preston 32% ready to use without any issues.
I was just wandering why I have reversed polarity when using a volt meter.
 
I remember from the past something about an electrical charge when liquid is pumped through different metals bolted together like a timing cover to block that is referred to as 'electrolysis ' I believe but I think it can't be measured by a common DVM, maybe measured in seized bolts in a typical block.
Then again I may be just rambling :scratch:
 
I remember from the past something about an electrical charge when liquid is pumped through different metals bolted together like a timing cover to block that is referred to as 'electrolysis ' I believe but I think it can't be measured by a common DVM, maybe measured in seized bolts in a typical block.
Then again I may be just rambling :scratch:

Yeah but.... The material your radiator made from would have an effect. The material your heater core was made from, etc...

Anything under half a volt on your average Walmart voltmeter is kinda suspect. It is not uncommon to see full 1 to 2 volt swings on some meters.

Is seem like it would be more telling to measure the resistance of a coolant sample but even that doesn't account for metal contamination.
 
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My comment on swapping the leads was a joke.

When you guys come up for air from this deep hole of "not gonna make a damn bit of difference" let us know. If the fluid checks good with a hydrometer and is not discolored move on down the road.
 
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lmao... WTF is this whole conversation?! lol I mean, lord knows I'm all for overthinking everything, but if I didn't like the look, smell, taste, feel, or sound of my coolant, I'd just replace it. Would take as much time as reading this thread did... except for the annoying air pockets.
 
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