Preventative Car Maintenance is Easy With a Homemade Radiator Monitor

Know your car's cooling system is in good shape using MOTHER's homemade radiator monitor, including parts layout, circuit board, how it works, building the monitor, installation and bill of materials.

| September/October 1985

You can drive with confidence using MOTHER's homemade radiator monitor. (See the radiator monitor photos and diagrams in the image gallery.)

You don't have to be a mathematical wizard to figure out that it's a lot less expensive to keep and maintain an old car than it is to regularly trade up to a new one. The drive-it-off-the-lot depreciation of $1,000 to $2,000 is just the beginning of the financial headaches awaiting the new-car addict. Nonetheless, millions of people buy a new car every three to five years just for the security of having a reliable vehicle.

Well, the key to feeling secure in (and making peace with) an older car—whether you're an accomplished mechanic or a complete klutz—is preventive observation. No matter who does the wrenching, it's always cheaper to catch a problem before it becomes a disaster . . . and nine times out of ten, simple anticipation will save you from being stranded. For example, a water pump seldom fails precipitously and costs only $30 to $60 to replace, but replacing an engine destroyed by heat—the inevitable result of continuing to drive with a bad water pump—could easily set you back ten times that amount.

Unfortunately, few cars are equipped with the gauges you need to properly monitor the condition of your auto's power plant. And those little red indicators on the dash are, in most cases, of little help in prevention. The threshold for such "idiot lights" is so high that they often don't come on until after damage has been done.

For these reasons, no experienced auto recycler would consider driving an "experienced" car that wasn't equipped with a water-temperature gauge; this simple instrument warns of all sorts of maladies (including some that go beyond cooling system troubles) before it's too late. But even the water temperature gauge gives only an indirect warning of low fluid level in your radiator.

One of the best ways to monitor the condition of your car's cooling system is simply to check the coolant level frequently; antifreeze loss is the primary sign that something is going wrong. And with modern-day electronics, we can take the concept of frequent checks to the extreme: With the simple radiator monitor I'm about to show you how to build, you'll have an electronic watchdog keeping an eye on your coolant level every second that you drive . . . helping you to get more years out of an old car or to protect a new vehicle against a premature death. You'll know instantly, courtesy of a flashing light, whenever the level drops below normal.

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