DFW summers are brutal on commercial vehicles. Here's what to do before and during the hottest months to keep your fleet running reliably.
Why DFW Summers Are Hard on Fleets
Dallas-Fort Worth summers are among the most demanding in the country for commercial vehicles. Temperatures regularly exceed 100°F, and heat index values can push well above that. Vehicles sitting in the sun reach interior temperatures of 150°F or more. Asphalt surfaces can hit 160°F.
This extreme heat stresses every vehicle system: cooling systems work at maximum capacity, batteries discharge faster and fail sooner, tires run hotter and wear faster, and engine oil degrades more quickly. Fleets that don't prepare for summer pay for it in breakdowns, repairs, and downtime during the busiest months of the year.
Cooling System Preparation
The cooling system is your first line of defense against summer heat. Before temperatures climb, have every vehicle's cooling system inspected: coolant concentration and condition, radiator cap pressure rating, thermostat operation, water pump function, and all hoses and clamps.
Coolant should be tested for freeze protection and corrosion inhibitor levels. Old coolant loses its protective additives and becomes acidic, corroding cooling system components from the inside. If coolant hasn't been changed in 3+ years, change it before summer.
Check radiators for debris accumulation. Bugs, dirt, and road debris clog radiator fins and reduce cooling efficiency. Clean radiators with compressed air or low-pressure water before summer. A clogged radiator that's fine in March can cause overheating in July.
Battery Testing and Replacement
Heat kills batteries faster than cold. The chemical reactions inside a battery accelerate in high temperatures, causing faster degradation and shorter life. A battery that's marginal in spring will often fail in the middle of a July heat wave.
Test every battery under load before summer. A voltage test alone doesn't reveal battery health — a load test shows whether the battery can actually deliver the cranking power needed to start a hot engine. Replace any battery testing below 80% of rated capacity.
Check battery terminals and connections for corrosion. Heat accelerates corrosion, and corroded connections cause starting problems and electrical issues. Clean terminals and apply anti-corrosion treatment as part of summer preparation.
Tire Management in Summer Heat
Tire pressure increases as temperatures rise — approximately 1 PSI for every 10°F increase in temperature. A tire properly inflated at 65 PSI on a 70°F morning may read 70+ PSI when the vehicle has been sitting in the sun for hours.
Check tire pressure in the morning before vehicles go into service, when tires are cool. Don't bleed air from hot tires to reach the target pressure — the pressure will drop when the tire cools, leaving it underinflated.
Inspect tires for heat-related damage: sidewall cracking, tread separation, and bulges. Heat accelerates rubber degradation, and tires showing these signs should be replaced before they fail on the road. Summer is the worst time for a tire blowout.
Air Conditioning Maintenance
Working air conditioning isn't a comfort item for DFW fleet drivers — it's a safety requirement. Heat stroke and heat exhaustion are real risks for drivers working in vehicles without functioning AC during a Texas summer.
Have AC systems inspected and recharged before summer if needed. Check refrigerant levels, compressor operation, condenser condition, and cabin air filter. A dirty cabin air filter significantly reduces AC effectiveness.
Address AC problems immediately. A driver working in a vehicle with failed AC in 105°F heat is a safety liability and a productivity problem. Don't defer AC repairs during summer months.
Summer Maintenance Schedule
Build a summer preparation checklist and complete it for every vehicle before June. Include: cooling system inspection, battery load test, tire inspection and pressure check, AC system check, belt and hose inspection, and fluid level verification.
Shorten oil change intervals during peak summer months for vehicles operating in extreme heat. Heat degrades oil faster, and the cost of more frequent changes is minimal compared to the cost of engine damage.
Onsite Auto Maintenance performs summer fleet preparation at your location, working through your fleet systematically before the heat arrives. Getting ahead of summer maintenance prevents the breakdowns that always seem to happen on the hottest days of the year.