Originally Posted By: i_hate_autofraud
Originally Posted By: SHOZ
You can use a volt meter for testing coolant. Or pH strips, anything under a pH of 9 is trouble.
Quote:
Begin with a cold engine. Remove the radiator cap and start the engine. Set your digital multimeter to DC volts at 20 volts or less. When the engine reaches operating temperature, insert the positive probe directly into the coolant. Rev the engine to 2,000 rpm and place the negative probe on the negative battery terminal. If the digital meter reads .4 volts or less, your coolant is in good condition. If it’s greater than .4 volts, the electrolysis additives are exhausted, and you may be in the market for a new radiator, a water pump or a heater core in the future. All of those are far more expensive than a simple coolant change.
Sorry, the digital multimeter test does not work, it turns out the reading you get is related to coolant concentration, 50/50 mix measures higher
then 30/70 mix and 60/40 mix measures highest, etc. Tried this out here, in car and in glass beakers on the bench.
Then I found this PDF:
BOGUS COOLANT TEST – Pat Goss Blows It!
https://app.box.com/s/mc3kaetdmj38ebzomyscxe9wt8rvotdg
Turns out Pat Goss made this claim on YouTube and Motorweek, he later answered posts that
segment was incorrect.
If the engine is running, injector and ignition power, etc, on the engine creates a normal
voltage drop thru the return path to the battery, usually .1 to .2 V DC that adds to the meter reading!
If you change your meter over to the lowest DC amps range with a probe in the coolant, you'll see a current
from 1 to 20 Micro-amps (.000020A). Corrosion is actually a current issue rather the voltage and you'd need
current in the high milli-amp range (.010A +)for a corrosion problem due to currents and dissimilar metals, etc,
I'll stick with Ph test strips or change GM Dexcool sooner. I also have another car in the garage that runs regular glycol
and it responds the same way.
Are they applying 14V to the metal or just using the meter? I don't seee that mentioned.