While proper preventive maintenance is important year round, summer temperatures can create a different set of maintenance needs for Class 8 trucks. Tire pressures, electrical systems and coolant all need extra attention as summer approaches, and fleet operators can improve summer maintenance programs with these six tips:
Proper tire pressure helps improve tire life and fuel economy. Although tires should be examined in every preventive maintenance inspection, tires may need special care heading into the summer months for several different reasons.
First, fleet operators and drivers likely added air to tires in the winter months since tire pressure drops as temperatures decrease. But, as temperatures increase, so will the pressure, leading to the risk that tires could become overinflated as the thermometer rises.
“If you take what we just went through in the Northern climates, when you go from 20 below zero and come out of a season even at zero or even 32 degrees, air pressures could increase,” said Mike Hasinec, vice president, maintenance systems/support, Penske Truck Leasing.
Second, tires tend to run hotter and wear faster in the warm weather, according to Mike Woods, diesel education program manager at Universal Technical Institute’s Lisle, Illinois, campus. “Also, the tread portion of the tires become softer in the summer months, making them more susceptible to punctures from road debris such as metal objects, screws, nails, etc.,” Woods said.
What’s more, when air pressures are inaccurate, the tire flexes in ways it wasn’t designed to, changing the shape of the tire’s footprint, which also results in irregular wear patterns and reduced tread life. In addition, underinflated tires build up excessive heat, potentially causing premature failure.
Hasinec said that most casings you see on the side of the road in the summer months were damaged due to under-inflation. “It is critical to maintain proper tire pressure. When you don’t have a tire properly inflated, that tire’s temperature increases drastically,” he said.
“To improve tire care, some fleets have more specific tire checks performed during the driver’s pre-trip inspection or during the scheduled PM in the summer months,” Woods noted.
Hasinec suggested that fleet operators pay extra attention to trailer tires. “Probably the most neglected units are the trailers. There are three to four trailers per power unit and they don’t always get the same thorough inspection as a tractor does,” he said.
Checking and adjusting the tire inflation pressure with an accurate tire pressure gauge is critical. All tire pressure gauges used to measure tire pressure should be checked periodically for accuracy and calibrated as per the gauge manufacturer guidelines.
Hasinec said many people don’t realize that a growing number of battery failures take place in the summer. “In the past you’d see a lot of your battery failures take place in the winter,” he explained, adding that with new engine technology, particularly in sleepers where they located batteries under the cab, temperatures have increased and the number of battery failures in the summer months is on the rise.
Cooling and electrical systems should be checked regularly throughout the year, and inadequate or improper service of these systems can often lead to heatrelated failures during the hot weather. The engine radiator, EGR coolers and transmission cooler need to operate properly to maintain the proper engine and transmission temperatures.
Penske checks cooling systems on every preventive maintenance inspection, and Hasinec said it is important to maintain a good 50/50 mix throughout the year, noting that it helps with boiling points as well as freeze points.
Hasinec added that one of the more predominant things that are overlooked on a coolant system is the radiator cap. “They keep the systems under pressure, and 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. This can lead to electrical malfunctions caused by poor connections at the electronic control units, sensors and solenoids that control various vehicle systems,” said Woods.
The air conditioning system of the cab and sleeper bunk should be thoroughly checked before the summer. Be sure to check that the engine fan/clutch is activated and engages properly when the A/C system is turned on as per the OEM-recommended guidelines.
“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,” Woods said. “These faults should be investigated, repaired and cleared before the vehicle is placed back into service.”
Warm temperatures mean the reefer units on refrigerated trailers face higher demand. To ensure they run properly as outdoor temperatures increase, fleet operators should inspect them regularly.
The Technology and Maintenance Council recommends that cab heaters be operated about 15 minutes per month to keep the ductwork system clean and the heater controls in good working order. Some engine manufacturers also recommend the coolant line valves be shut off when operating the vehicle in very warm, ambient temperatures.