Scorching Heat Can Drain You and Your Car

Question: I have a 1988 Toyota Camry with 82,000 miles. Whenever I drive for long periods in hot weather, I have trouble starting the car. After I wait five or 10 minutes, the car starts up as if nothing was wrong. My mechanics can’t find a problem. --J.H.

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Answer: As master of a 1 1/2-ton machine, it is indeed a humbling experience to turn the key and hear nothing from the beast under the hood. Blame the scorching midday heat: It exacts a heavy toll on your car’s electrical system. Batteries put out less current on hot days, just when you need the most current. Heat can raise friction levels inside the engine and adversely affect the fuel system.

When you turn your key, the ignition switch activates a second switch under the hood, known as a solenoid, that opens up the current for the high power electric circuit that feeds the starter motor. The fact that nothing happens means either the problem exists in the low or the high power side of the system.

Here’s an easy test: Turn on your headlights and have someone stand in front of the car. Turn the ignition key. If the headlights do not dim, the problem is that the solenoid is malfunctioning or there is some other problem on the low power side.

If the headlights dim severely, (as they ordinarily should), then the solenoid is working. If so, then one of two problems exist: The starter motor is crapping out or the starter is starved for electrical power.

The starter motor might have a problem that shows up only when a severe load occurs. When you shut off a hot engine on a hot day, the latent heat in the engine continues to raise the temperature of the engine block.

Even a good starter motor will suffer if it doesn’t get enough juice, so you need to have the battery output checked and make sure the cable connections are clean.

Finally, the problem is most likely somewhere in the cables, solenoid, battery or starter motor. Less likely, the devil may exist in the low power wiring or ignition switch. A new starter motor could cost a few hundred dollars; a solenoid should cost less than $100.

* Vartabedian cannot answer mail personally but will attempt to respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, 1875 I St. N.W., No. 1100, Washington, DC 20006 or e-mail to ralph.vartabedian@latimes.com.