First of all, antifreeze and coolant are the same thing. You would be surprised at how many people have asked me if they should use coolant in the summer and antifreeze in the winter. Your cooling system’s job is to keep your engine parts from melting from the extreme heat produced by combustion. Automotive engine coolant has properties in it to keep it from freezing while the engine isn’t running, and this is why a lot of people call it antifreeze – another reason is manufacturers print "antifreeze" on the container.
Most auto manufacturers recommend a 50/50 mixture of coolant and distilled water to prevent freezing or overheating, but always check your owner’s manual for the proper type, mixture and frequency of flushing and replacing of your vehicle’s coolant.
At this time of year, when the temperatures start to get colder at night, you should test your vehicle’s coolant with a hydrometer to make sure it has the proper mixture so it doesn’t freeze up on you overnight.
To test your coolant using a ball type hydrometer:
- Remove the radiator or coolant reservoir cap – Make sure the engine is cold, so you don’t get sprayed with hot coolant.
- Start the engine and let it reach operating temperature.
- Insert the hydrometer tube into the coolant.
- Squeeze and release the bulb to draw coolant into the hydrometer. Follow the tools manufacturer's instructions for how much you will need to draw in.
- Count the number of balls that are floating to the top.
- Read the chart on the hydrometer to see what temperature your coolant is protected to.
Determine if you will need to strengthen the mixture. For example; if the number of balls floating indicates your coolant is good to -10 degrees, and temperatures in your area get down to -25 degrees – you’re going to need a stronger mixture.
If your system is full, you will have to drain some of the mixture out and replace it with concentrated coolant.