How to test engine coolant
Testing coolant freeze protection is just part of the picture
You can test coolant freeze protection with an inexpensive tester from any auto parts store. But protecting against freezing is only part of what coolant does. Coolant also lubricates and protects the radiator, heater core, tubing and water pump from corrosion.
The anti corrosion additives wear out long before coolant loses its freeze protection and old coolant can contain acids that damage the internal components. That’s why you can’t rely on a coolant freeze protection tester along.
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.
Test engine coolant with coolant test strips
Coolant tests strips come in various designs from 2-way
test strips up to 4-way strips. The 2-way strips measure glycol concentration and the coolant’s pH balance. 3-Way test strips measure glycol, pH and reserve alkalinity. 4-way strips measure Nitrite, Molybdate, Glycol and pH.
These tests tell you the actual condition of your coolant, not just its freeze protection.
The downside to using test strips is that they usually come in a bottle of 100 strips and that can be pricey. However, some companies sell smaller packs for DIYers.
You can also test the anti corrosion properties of your current coolant using a digital multimeter.
Here’s how to test coolant with a multimeter
Set a digital multimeter on 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.
If the coolant 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