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Discussion Starter · #1 ·
So the other day some guy in a thread I was reading mentioned something about this and to check your coolant with a multi-meter. So I thought hey why don't I try it and see..

So I check the coolant in my radiator cap using the ground on the battery and I have 0.28-0.30 volts in the coolant.. According to that guy if you have 0.30 or more you have some voltage leaking into the coolant or something, and he said to clean your grounds..

Well.. Where are the grounds for the 5.9, I see 2-3 on the fender by the battery.. I know another is on the drivers side cylinder head by the power steering pump.. Are there any others ? And if cleaning the grounds doesn't lower this number then what ? Or are the readings I got ok ? I know it isn't old coolant, because I did my plenum only like 2 months or so ago and the coolant is all fresh cept maybe some that was left in the block.. but the heads and radiator and intake were obviously completetly drained.

Could this be what is causing this white powder like stuff I see on the inside of the radiator when I take the cap off ?


EDIT: I just checked again cept this time with positive battery cable unplugged.. The reading is still 0.28v Plugged the battery back up and still 0.28v turned the Jeep on 0.28v.. So I guess it isn't a bad ground and more a chemical thing going on ?? So what can I do to stop this or is this voltage normal ? Like I said the coolant has been changed recently.. I didn't put any flush in it or flush it with a garden hose I just took my plenum apart drained the whole system and refilled it with distilled water and coolant
 

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Discussion Starter · #3 ·
Mmm well it says its its above 0.30 then you have a problem.. Mine is pretty much right at 0.30 almost.. I guess I just need to do a chemical flush of the cooling system like that link said. I think the reason I have a current in there is because of the aluminum oxide powder, I noticed when I put the positive lead from the multimeter on the powder and started rubbing it the voltage would go to 0.4v.. Im going to check the 4.0 too curious what that one is reading
 

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From what i was told when i was in college that test is good to determine if the coolant needs changed. metal that naturally is pulled from the block when coolant gets old creates electrolysis. i really just look for dirty coolant or change it every two years.
 

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Discussion Starter · #5 ·
Not true for me.. My coolant is fresh in both the 5.9 and 4.0,, The reason its there is either bad grounds or because there is still crap inside the cooling system that a water hose flush didn't get.. Aparently you have to flush the system with chemicals that clean the thing really well meaning drive the car with the flush in the system then drain everything and rinse the system out with a hose..

I talked to the guy who's link was posted above today about it.. He said my 0.30v is where aluminum starts to break down, and he said what I told you above.. Because my coolant is brand new in the system I just did my plenum and I checked my moms 4.0 today its 0.33v yet her coolant is new as well because I replaced the radiator not to long ago. So yea.. Ima buy 2 bottles of flush for my 4.0 and 5.9 and then 2 bottles of this stuff called electrolysis arrestor.. That stuff coats the metals in the system and keep them from conducting electrolysis with the other metals in the system.. Aparently after flushing with that stuff and using that bottle of arrestor the voltage will drop to near 0.02v so it says.. I might also buy an Anode which is like a lightining rod which takes the electricity in the cooling system and attracts it to itself so it will get eatin up and not engine and radiator/heatercore

Those bottles are kinda expensive tho $25 a pop.. but everywhere I read online says its the best stuff to use.. and its even recommended on that website kjk linked

http://www.sancarlosradiator.com/catalog.htm
 

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Ok just for grins I just checked mine. When I first stuck the + probe into the coolant, I was at .30V. However, within a second or 2, the reading started to drop. Within about a minute and a half it was down to .08V. Weird? BTW I just did a flush and coolant change less than a week ago.
 

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Discussion Starter · #7 ·
I think yours is fine.. Mine stays 0.28 on my 5.9 and 0.34 on my 4.0 . On the 4.0 it did it like yours it read .40v then a second or two later it was 0.34
 

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I think yours is fine.. Mine stays 0.28 on my 5.9 and 0.34 on my 4.0 . On the 4.0 it did it like yours it read .40v then a second or two later it was 0.34
If it is ground related in any way, I'll also mention that I thought I had ground issues causing my stereo to act up so I added a 6 gauge ground wire from my - terminal to the exhaust manifold stud next to the battery about a month ago.
 

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Discussion Starter · #9 ·
Mine isn't ground related if I unplug my battery my voltage still reads the the same
 

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Electrolysis in the coolant is normal - you have dissimilar metals, often with head, in a bath with free ions.

However, you don't check "coolant voltage" against the battery negative terminal - put one probe (usually the positive) directly in the coolant, touching nothing; and the other (usually the ground) to touch a BARE METAL part of the cooling system (usually the radiator neck.)

Indicated voltage over 1.0VDC tells that the coolant has worn, the corrosion inhibitors are failing, and you need to flush & refill your system.

Checking the voltage between the coolant and the battery ground tells you nothing.

This is an "old-school quick-test" to gage the state of the coolant. A hydrometer is used to check the mix ratio, the voltage test is a more reliable indicator of coolant state.
 

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Discussion Starter · #11 ·
What is the different between checking the battery ground and the bare metal of the cooling system ? According that link KJK linked they say to use the battery ground. The battery is grounded the radiator isn't from what I understand... Aluminum gets eatin away at 0.30v or higher according to what I have read and iron starts at a higher voltage.. I understand the disimiler metal thing iron and alum together with an electrolyte environment is basically like a small battery together, but why then would some people have no voltage reading like the guy above in my thread and I have voltage readings ?

Go on google every link you click on says to use the battery ground.. Im not saying your wrong but it sure seems like it ? One link I did find says to use the battery neg terminal, and then like you said to switch the negative lead to other parts of the vehicle like the engine, the body the vehicle and so forth. I guess Ill go out there and do what you said and see what happens..

But I still think that's wrong to check the cooling parts... If they have an electrical current going through them, then how are you going to use them as a ground....

http://www.ve-labs.net/electrolysis-101/how-to-test
 
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