Depending on where you are in the world, you just might be gearing up for the hottest days of summer. But are your vehicles ready? With the right combination of inspections and tasks, you can keep the fleet running smoothly, saving you time and money while protecting your organization from compliance and legal liabilities. So, we reached out to some of the experts at Eptura for their best advice on fleet summer maintenance and how to ensure your fleet can beat the heat. 

What is fleet summer maintenance? 

Summer fleet maintenance is all the preventive maintenance inspections and tasks you schedule to prepare your vehicles – everything from rental cars, taxi cabs, trucks, heavy machinery, and buses – for the demands of summer. It’s how you keep your fleet rolling safely and without busting your budget. 

It can include simple inspections like checking fluid levels to more involved tasks like swapping in summer seasonal tires. Depending on the vehicle, you might also want to change the equipment you carry in the trunk. In winter, you need to carry a brush and scrapper for icy windows, but in summer, a sunshade for the front windshield keeps the interior cool. 

Why is fleet summer maintenance important? 

You could likely list ten critical PMs for winter—plus all the reasons behind them, but when it comes to summer maintenance for your fleet, it can be harder to think of what to do and why we need to do it.  

Winter constantly reminds us that it’s winter. Every time you drive, you have to: 

  • Put on a warm jacket and boots 
  • Walk to the vehicle over an icy path 
  • Start the vehicle and let it warm up 
  • Drive carefully to compensate for snowy, icy roads 
  • Keep an eye on the climate controls to keep the windows clear 

You can add “Curse the weather under your breath” anywhere on that list.  

In summer, though, you can jump in your car and just go. But just because summer is easier on you doesn’t mean it’s easier on your vehicles.  

“Any time you have extreme temperatures – whether you’re talking about extreme cold or extreme heat – that taxes the vehicle and specific systems,” explains John Crichton, director of field support at a manufacturer of commercial and defense vehicles and engines, in Fleet Maintenance. 

In fact, it’s likely that heat is harder on vehicles than cold. 

Heat is harder on your fleet than cold, and it’s only going to get worse 

Some quick examples: In winter, your engine is so good at generating heat you can use the excess to warm up the cabin. But in summer, the only way to stay cool is by running the AC system. A dead battery in winter might only need a quick jump. In summer, you’re dealing with heat that accelerates corrosion on the terminals and can eventually evaporate the battery’s acid. You won’t need cables. You’ll need a new battery. 

The worst thing about fleet and the heat? According to The Washington Post, the situation is only going to get worse, with average summer temps a full 1.7 F higher than from 1971 through 2000. Summer maintenance has always been important. It’s set to become critical. 

Warm weather also means more people on the road, so more stop-and-go traffic and accidents 

On American roads, summer holidays are synonymous with heavy traffic. In fact, summertime’s Fourth of July, Memorial Day Weekend, and Labor Day Weekend are three of the top five holidays with the busiest roads. In Australia, the two big days for summer traffic are December 27th and January 2, right in the middle of the country’s two warmest months. 

The last few years, travel numbers overall were down, creating a lot of pent-up desire to get out and see the world again. This year, a combination of inflation, airline ticket prices, and concerns over flight disruptions are pushing more people out onto the roads for holiday travel. According to a report by NBC News, the percentage of vacationers driving instead of flying to save money rose 10 percentage points, from 16% to 26%. 

All those extra drivers mean more stop-and-go traffic even on highways, putting more pressure on every part of your vehicles, from the engine to the brakes. It also means more unsure drivers behind the wheel, increasing the risk of accidents and the importance of every safety feature, from basic seat belts to high-tech lane departure warnings. Remember, all those vacationing drivers are driving on unfamiliar roads, for long hours, when they’re only used to driving short distances to and from work and the local grocery store. 

What should you include on your fleet’s summer maintenance checklist? 

There’s more than one way to make your list of summer maintenance PMs. Some industry experts recommend a “system smart” program. Instead of looking at individual parts, you look at all the parts within specific systems, including: 

  • Serpentine 
  • Timing 
  • Cooling  

For the air conditioning, for example, you can start by simply checking that the fans work at all the different speeds. Start at the lowest and work your way up, checking the different vents around the cabin to ensure none are blocked. Next, check for any strange sounds, including banging, squealing, or squeaking. First, do your sound check in the cabin. Next listen to the AC run while standing in front of the engine with the hood open. While checking for any sounds, see if you can smell anything coming from the vents. Strong or strange smells are an indication of mold or some sort of rot. 

A common cause of problems is leaks, which you can systematically check for using a fluorescent leak tracer for car AC. Another common source of issues is the compressor. To check it, look to see if the center pully is turning properly. If it isn’t, it could mean the compressor’s clutch is not engaged, a possible sign of:  

  • Broken pressure switches 
  • Faulty or flipped fuses 
  • Bad or crossed wiring 
  • Low levels of refrigerant 

System-based PM programs make a lot of sense, because they match how we tend to think about vehicles. But you can also build your summer preventive maintenance program by focusing on specific parts or types of parts. Here, you should include tires, engines, radiators, batteries, and brakes. 

Check your tires: Inflation is now a good thing  

“Proper tire inflation is important for everyone’s safety. With the heat, tires expand and become softer, leading to an increased risk of road-debris punctures, “explains Andrew Mills, an Account Executive at Eptura. 

It varies by tire size, style, and manufacturer, but as a rule of thumb, a tire gains one to two pounds per square inch for every 10-degree rise in the outdoor temperature. At the same time, an underinflated tire loses its shape, creating an uneven footprint and irregular ware patterns. Worst-case scenario, an underinflated tire generates enough excess heat to cause a blowout.     

Maintaining the right tire pressure is also important for your budget. Properly inflated tires deliver better fuel economy and a longer useful life. 

When checking tire pressure, make sure to follow the manufacturer’s recommendations. It’s also important to invest in quality tire pressure gauges, so your readings are both accurate and precise.  

Check your engines: Check coolants, lubricants, and filters 

“Make sure to check all your coolants, lubricants, and filters. You need to ensure the engine can efficiently shed heat. You also need to make sure it’s not generating too much heat to begin with,” says Brandon Gunn, Senior Account Executive at Eptura with over 20 years’ experience helping fleet managers find the right software solutions for the vehicles.  

From there, you can look at: 

  • Timing belt 
  • Alternator 
  • Water pump 
  • Idler pulleys 
  • Thermostat 

Check your radiators: How to not blow a gasket 

“There are a lot of important PMs for the radiator because it’s how you keep the rest of the engine from overheating,” says JP Mariano, an enterprise asset account manager at Eptura. 

In fact, any PMs you set up are sure to deliver a solid return on investment. In an article for Fleet Magazine on summer radiator maintenance for your vehicles, Randy Pruitt, CEO of a manufacturer, re-manufacturer, and distributor of aftermarket cooling products for heavy-duty transportation, commercial, industrial, and agricultural industries, explains how head gaskets and coolant are relatively cheap but protect you from expensive repairs. Worst-case scenario, overheating can force you to replace all internal components or even the entire engine.   

Pruitt recommends setting up PMs to check for debris that might restrict airflow in the: 

  • Charge air cooler 
  • AC condenser 
  • Radiator 

You should also look at look at the fins to ensure they are not folded or corroded. He also suggests checking the coolant for additive levels and double-checking all the hoses and clamps.  

Check your batteries: Check the charge and clean  

“Make sure the battery is fully charged. Heat can drain a battery over time, so you want to start from 100%. You can also carefully clean the top of the battery, removing any road grit or grease, which can also affect the charge,” suggests Matt Weese, a Senior Account Executive at Eptura with a decade of experience working with enterprise asset and fleet management solutions. 

Make sure to look closely at the terminals and remove any signs of corrosion. According to advice from Continental Battery, corrosion on the terminals can lead to a shorter lifespan and even damage to the vehicle’s electrical systems. Once you’ve cleaned the terminals, you might want to apply dielectric grease or battery terminal protector.  

Corrosion can also be a sign of other problems. If there’s only corrosion on the positive terminal, you might have a problem with your voltage regulator, leading to overcharging. But if it’s on the negative terminal, you have undercharging, which is often the result of frequent shorter trips where you’re using a lot of onboard electronics.  

Check the brakes: Put a stop to bad brakes 

For all the hassles of a vehicle that won’t start, nothing compares to the dangers of one that won’t stop. From the immediate risks to your drivers, vehicles, cargo, and everyone else on the roads to the insurance, civil, and even possibly criminal liabilities, brake failures are an overall disaster. 

“Start setting up a summer PM program for your brakes with the certainty that they’ve taken a lot of punishment over the winter months. Cold temps, snow and ice, as well as the sand and salt on the roads can wear out and weaken braking systems,” says Douglas Myers, a Senior Enterprise Account Executive with over a decade of experience in the enterprise asset management industry. 

So, inspect everything, including: 

  • Fluids 
  • Pads 
  • Lines 
  • Hoses 

Also make sure to include all the parking brakes in the PMs. 


Summer fleet maintenance is the combination of inspections and tasks you need to ensure your vehicles can beat the summer heat. Although we often think of winter as the hardest season, in many ways, heat is harder on vehicles than cold, making summer maintenance critical to running an efficient, profitable fleet. Start by looking at the AC system in your vehicles. Check for leaks and problems with the vents.

From there, you can look at tires, engines, radiators, batteries, and brakes. For tires, you need to focus on inflation, keeping in mind how high temperatures can affect air pressure. For the engines, check, replace, and top off fluids and lubricants as needed. Your radiator keeps the rest of the engine cool, so make sure it’s working.

You can see a large ROI here because although the parts and service steps are relatively inexpensive and easy, they can help you avoid difficult repairs. Make sure your batteries are all properly charged and that the terminals are free of any dirt or corrosion. With your brakes, you need to check everything.

Winter is hard on all parts of the system and summer means more stop-and-go traffic with more drivers on the roads. 

About the author

Jonathan Davis

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