Summer car care: June to September, when the heat does the testing

June to September

The short list

1. Coolant level, mix and condition

   The one fluid that keeps a 100 F afternoon from becoming an overheated engine. Checked at every visit; a flush restores the mix if it is weak or old.

2. A/C performance

   Vent temperature and pressures checked; recharge only if the system is low. The condenser also adds heat to the radiator's air, so a weak cooling system shows first with the A/C on.

3. Oil level and interval

   Heat and full-load mountain driving are severe service. Keep the level full and the interval on the sticker, and consider full synthetic if the manual allows it.

4. Tire pressure

   Hot pavement raises pressure; set it cold to the door-jamb figure, not the number on the sidewall.

5. Engine and cabin filters

   Summer dust and smoke load both. Checked and shown to you.

6. Transmission fluid

   Heat shortens fluid life. The check reads level and color; a service is due if it has gone brown.

7. Battery

   Heat quietly damages batteries more than cold does; the fall failure often starts in August. A test at a participating location finds it early.

8. Wipers and washer fluid

   Sun bakes the rubber; bugs and dust use the fluid. Both are quick in the bay.

Summer in Northern Nevada is dry heat, which sounds gentle until you are in traffic on South Virginia Street at 4 PM with the A/C on full and the gauge creeping. The airport's July normal is a 93.9 F high with 24 days at or above 90 F; August is nearly the same, and Minden runs just as hot. The engine makes more heat in those months than at any other time, and the cooling system has to move it through air that is already 95 F. This page is the summer list.

Coolant is the summer fluid

Everything about summer under the hood comes back to the cooling system. Old coolant with worn additives moves heat more slowly. A mix thinned by water top-offs boils sooner. A cap that no longer holds pressure lowers the boiling point further, which matters at Reno's 4,500 feet. None of those shows up in May. All of them show up in July on the Mount Rose grade.

The maintenance check at every oil change reads the level and condition and looks at the cap and hoses. If the fluid is tired, a coolant flush puts the manufacturer's mix back. Our coolant and Reno summers post goes through the 65-day heat season in detail.

A/C: recharge is not the whole answer

An air conditioner that blows cool but not cold is usually low on refrigerant, and an A/C service recharges it after checking pressures. But a system that is low every summer has a leak, and a compressor that will not engage is an electrical or mechanical fault. The technician tells you which one you have; a recharge fixes the first and not the others.

The A/C also loads the engine and heats the radiator's air, so a car that overheats only with the A/C on is telling you about the cooling system, not the A/C. Our A/C blowing warm page walks through the causes.

Oil under heat and load

Oil thins as it heats, and a summer of 90 F afternoons plus Tahoe weekends at full load is the severe schedule in your manual. Full synthetic holds its viscosity under heat better than conventional, which is one reason many manuals now specify it. Keep the level full; a quart low in July is harder on the engine than a quart low in January.

Towing a boat to Pyramid Lake or a trailer to Topaz adds to it. The towing guide covers what the differential and transmission need when the hitch is in use.

The summer rush and when to beat it

The bay fills twice in summer: the week before Memorial Day and the Fourth of July with road-trip prep, and the first real heat wave with A/C and overheating complaints. The quiet windows are early June and late August on a weekday morning. The Longley Lane service center closes at 3 on Saturday, an hour earlier than the other Reno service center, so plan a Saturday visit for the morning.

If you are heading over the pass or down 395 for the weekend, the road trip checklist is the short list for the night before. Otherwise, pull into the nearest service center before the heat wave, not during it, and no appointment is needed at any of the four service centers.