Rick's Free Auto Repair Advice

How to test antifreeze

You need more than a tester to test antifreeze

Test antifreeze anticorrosive additives too

You can test antifreeze freeze protection with an inexpensive tester test antifreezefrom any auto parts store. But protecting against freezing is only part of what antifreeze does. Antifreeze also lubricates and protects the radiator, heater core, tubing and water pump from corrosion.

Antifreeze anti corrosion additives wear out long before it loses its freeze protection

Antifreeze contains many additives. There are anti-foaming agents, lubricants, seal conditioners, corrosion inhibitors, and anti-electrolysis agents. As coolant ages, these additives wear out. Each of these additives prevents damage to critical engine parts.

However, the most important are the anti-corrosion additives, 0nce that wears out the dissimilar metals in the cooling system begin swapping electrons, causing significant and costly damage.

Cooling system corrosion causes heater core failure, radiator cloggs and leaks, rapid water pump and seal wear and heater tubing rust out. Replacing a heater core in most late model cars involves removing the entire dash, evacuating the A/C system and the complete dis assembly of the heater box and duct-work. That’s every bit of a $1,000 repair. You can prevent it by performing regular coolant changes.

Here’s how to test antifreeze

Set a digital multimeter the DC scale for around 12 volts. Attach one of the test leads to the negative battery terminal and submerse the other end into the coolant. Then rev the engine to 2,000 RPM and read the voltage on the meter.

test antifreeze with multimeter

If the antifreeze test reads over .3-.4 volts, it means that the coolant is conducting too much electricity. Either the coolant needs replacing or you have a grounding problem in the vehicle. If the coolant is fresh, check for poor ground connections between the engine and the firewall and the engine and the negative battery terminal.

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat


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