Checking coolant with multimeter

Ok, so I saw a YouTube video showing how to check your coolant with a multimeter. Person in video says if your coolant reads below .03 on the 20 volt DC setting your coolant is good. I decided to give it a try. Mine reads .25 . Anyone ever try this with the Toyota coolant? I'm wondering if there's an additive in it that would make it read so high.

I've been draining the radiator and filling it up with new Toyota coolant every 20-30k. Not a complete flush but I figure adding new coolant every so often will keep it somewhat fresh. Is this a bad idea?

 

Never used a meter but I do drain the radiator and fill every 30k. I'm sure Toyota says it's lifetime but I'd like to stretch the lifetime.

 

I believe it's actually 0.4 or less is good.

 

As @4Running Daily suggests, the correct target is .4

Your .25 is just fine.

 

Can't resist, same number on blinker fluid?

 

No, there is requirement for conductivity to support the blinker circuit. Doh! So the number needs to be much higher!

 

You are really overcomplicating this. If a five dollar parts store hygrometer says the coolant is okay it's okay. Leave it alone.

 

In don't have a 5 dollar parts store hydrometer but I did have a multimeter on hand and went that route.
I'm pretty sure the magic number should be .04 or under not .4

 

If it ain't low leave it alone, forever.

 

Wat?

 

It's over analyzing a simple liquid. If it's been changed regularly then its ok. I've never seen anyone test coolant for voltage except in rare cases to confirm the coolant is causing failure. But its 20$ a jug, if you're worried, dump it. It's premixed and the days of overstrong coolant are past us.

The acidity in the oil is more of a concern for me than the acidity in the coolant. It just happens that you can actually measure the coolant.

 

How do you use a multimeter set to DC voltage to test your coolant? Where do you stick the test leads, one to the pos terminal and stick the other one in the radiator? I can't think of how this test would be reliable.

 

If coolant is left in an engine system for too long, it can build up acidity similar to how a flooded battery works. It will build voltage and eat gaskets and metal. It's one of the reasons for changer intervals with coolant.

 

I can see the coolant gradually having more metal content therefore being more conductive. I just don't see how it can generate voltage on it's own.

 

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=905034

http://www.familyhandyman.com/automotive/car-maintenance/coolant-testing-with-a-multimeter/view-all

 

Google is your friend

http://www.familyhandyman.com/automotive/car-maintenance/coolant-testing-with-a-multimeter/view-all

 

Thanks Bill. Here's another question. Do you think your multimeter is accurate? Unless you spent decent money on a Fluke or better DMM I wouldn't trust it in the millivolt range. I still think the test is a poor one.

 

I have a Fluke.

The only cheap tools I buy are one time or very infrequent use items that I don't really care if they break, and if it doesn't work right won't get me killed.

 

So do I . I've been a calibration tech/semiconductor equipment mechanic for a long time. Sticking a test lead into a liquid just does not scream accurate to me.

 

I've been turning wrenches and I am ASE certified. Never once have I heard of this.