Seasonal

Getting ready for an East Tennessee summer

Two things fail in an East Tennessee summer: air conditioning and tires. Both give warning, and both are cheaper to deal with in April than in July when every shop in Knox County is booked solid.

Test the AC before you need it

The first 90-degree week is when every shop in the region gets slammed at once. Run the AC on full for ten minutes in spring. If the air is cool but not cold, or it cools at speed and goes warm at idle, the system is low — and low almost always means a leak. Getting that found in April costs the same as in July, but you are not sitting in a hot car for a week waiting for an opening.

Heat changes your tire pressure

Pressure rises roughly one PSI for every ten degrees of temperature increase, and hot pavement adds more. That sounds harmless, but a tire that was already low in February is now running hot and flexing at the sidewall, which is how highway blowouts start. Check pressure cold, first thing in the morning, against the sticker in the driver's door jamb — not the number on the tire sidewall, which is a maximum rather than a recommendation.

Old rubber and hot asphalt

Heat accelerates everything that is already wrong with an aging tire. If yours are cracking at the base of the tread blocks, or the DOT date code says six years or more, summer interstate driving is the worst possible time to find out how much life is left. This is the season we see the most blowouts on I-40 and I-75.

Cooling system, while you are at it

Summer traffic on Alcoa Hwy or Kingston Pike is where a marginal cooling system finally overheats — sitting still, no airflow, AC adding load. A pressure test finds a weeping hose or a tired radiator before it strands you in the slow lane.