100-Degree Days: What Kansas Summer Heat Breaks

Everyone worries about their car in January. Statistically, August is harder on it. Start with the battery, because this is the one that surprises people. Heat is the primary killer of batteries — high under-hood temperatures accelerate grid corrosion and drive off electrolyte. The battery that leaves you stranded on a cold morning usually died in July. Cold just collected the debt. The cooling system is a system, not a jug of green liquid. Coolant condition and freeze and boil points, the radiator cap — which holds the pressure that raises the boiling point, so a weak cap causes overheating with no visible leak anywhere — the water pump, the thermostat, and the cooling fan or fan clutch actually engaging. Then there's a failure cause you don't read about on national car blogs: radiator fins packed solid with bugs, cottonwood, and harvest chaff. We see it every year. Hoses fail from the inside out, so looking at them proves little. Squeeze them. A hose that feels mushy, or crunchy, is done regardless of how it looks. Tires are the summer safety item. Blowouts spike in heat, and the recipe is always the same: underinflation, pavement well over 100 degrees, and sustained highway speed. Check pressures cold and check the age while you're at it — the DOT code on the sidewall ends in four digits for the week and year the tire was built. Age matters independently of tread depth. On air conditioning: weak cooling almost always means the refrigerant is low, and refrigerant doesn't get used up. Low means there's a leak. Recharging without finding it is treating a symptom you'll be treating again next summer. Worth knowing that older vehicles use R-134a while most newer ones use R-1234yf, and the two systems aren't interchangeable — different fittings, different oil, and a large difference in what the refrigerant costs. And the cabin air filter, again. Half the "my vents aren't blowing hard" complaints we hear are a filter that hasn't been changed in years.