Surprisingly, in my repair shop, we find one of the most neglected parts of the average car is the cooling system. Seems that a lot of people look at it as, “out of sight; out of mind.” They don’t pay any attention to it. But in reality, you should be checking the coolant in the cooling system at least once every year. Now, regardless of what the owner’s manual says - the owner’s manual may say that the coolant is designed to last up to 5 years or 150,000 miles – that doesn’t mean it will. So be proactive and check it before it does damage.
One thing you can do is use a simple hydrometer like this; draws some coolant up inside, and tells you the freeze protection. It also tells you if the coolant is still clear and the proper color. But a better way to do it is right here. These are coolant test strips. You dip these into the coolant, then the little pads on them change color, and you compare that color with the colors on the side of the bottle, and it tells you whether the coolant is good or bad.
Now, another test, and this one is a little sophisticated, but you need a simple volt meter – you set it on DC volts – you connect the negative cable to the negative terminal of the battery; then with the radiator cap off and the car running at about 2,000 RPM, you dip the red probe into the coolant, like so, and you get a reading on here. That reading should be less than 4/10 of one volt. If it exceeds 4/10 of one volt, the coolant needs to come out, the system flushed, and if that doesn’t take care of it, you need to check the electrical system on the car.
Also, the coolant that you put into it? Well, one size doesn’t necessarily fit all. So you want to look in your owner’s manual. There should be a number, a qualification number or an ASTM number; make sure that that number appears on the container of the coolant that you’re buying. Always use distilled water. You mix the coolant and the water, 50/50, outside of the car, then you put the mix into the car. You never put just plain water and plain coolant, because that can upset the balance in the system. Take care of that, and you’ll never have any cooling system problems. We hope.
And if you have a question or a comment, drop me a line right here at MotorWeek.