Focus on Specific Maintenance Items as Temperatures Rise

Penske Truck on Highway

The summer months bring warm temperatures, and certain maintenance items can benefit from extra attention and regular checkups to prevent costly fixes down the line. Proper maintenance is crucial throughout the year, but Mike Hasinec, former vice president of maintenance support at Penske Truck Leasing, said carriers and their maintenance providers should pay special attention to specific items at the peak of summer.


Proper tire pressures improve safety as well as tire life and fuel economy, and tires need special care when temperatures increase. Tires tend to run hotter and wear faster in the warm weather, which means the tread portion of the tire becomes softer in the summer months, making tires more susceptible to punctures from road debris such as metal objects, screws and nails.

Checking and adjusting the tire inflation pressure with an accurate tire pressure gauge is critical, and tire pressure gauges should be checked periodically for accuracy and calibrated as per the gauge manufacturer guidelines, Hasinec said.

When air pressures are inaccurate, the tire flexes in ways it wasn’t designed to, changing the shape of the tire’s footprint, resulting in decreased fuel economy, irregular wear patterns and reduced tread life. Also, underinflated tires build up excessive heat, potentially causing premature failure.

Fleets also face the risk of over-inflated tires since tire pressures increase as temperatures rise.

Hasinec suggested that carriers pay extra attention to trailer tires, which are often neglected.

To improve tire care, some fleets have more specific tire checks performed during the driver’s pre-trip inspection or the scheduled preventive maintenance (PM) in the summer months.

Cooling and Electrical Systems

The engine radiator, EGR coolers and transmission cooler need to operate properly to maintain the proper engine and transmission temperatures, and inadequate or improper service of cooling and electrical systems can lead to heat-related failures during the hot weather.

Penske checks cooling systems on every preventive maintenance inspection, and Hasinec said it is vital to maintain a good 50/50 mix throughout the year, which helps with boiling points as well as freezing points.

Hasinec added that one of the more predominant things that is overlooked on a coolant system is the radiator cap, which keeps the systems under pressure. “You should pressure test those when you pressure test the system,” he said. “The caps today are better than they used to be, but they still fail.”

Electronic component failures can be caused by damaged or missing heat guards, heat shields or heat deflectors, especially within those components found near the exhaust system after-treatment devices. Excessive heat can also melt or make the plastic electrical connectors brittle, leading to electrical malfunctions. This is caused by poor connections at the electronic control units, sensors and solenoids that control various vehicle systems.

Air Conditioning Systems

Demands on air conditioners in the cab and the sleeper bunk are increased in the summer months, and the units should be checked regularly. Technicians need to ensure the engine fan/clutch is activated and engages properly when the A/C system is turned on. Also, the A/C system typically interfaces with the electronic engine controls and abnormal operation conditions within the A/C refrigerant subsystem could trigger fault codes, which need to be investigated, repaired and cleared before the vehicle is placed back into service.

Refrigeration Units

Clearly, warmer temperatures mean the reefer units on refrigerated trailers face higher demand, especially with frozen items, Hasinec said. Penske Truck Leasing typically services equipment every 90 days or less, depending on the number of hours the unit runs, and Hasinec recommended that fleets using refrigerated units make equipment available for service at regular intervals. Moreover, drivers and carriers should inspect the units regularly to ensure they’re running correctly.


Hasinec said the number of battery failures in the summer months is on the rise, particularly with new engine technology. In the past, battery problems typically took place in the winter.