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8 Most Common Heavy-Duty Truck Failures Caused by Heat

As the dog days of summer approach, extremely high temperatures, especially during these summer months, can have various impacts on a heavy duty truck, potentially leading to mechanical breakdowns if not effectively managed. This is a potential danger if your truck is down due to a malfunction or fault code that has appeared.

Heat can be a truck's worst enemy, often leading to frequent and costly breakdowns. We'll explore and unpack the 8 most common truck failures caused by heat and how OTR Diagnostics can aid with high heat situations!

1. Engine Overheating

Engine overheating is a common issue in trucks, especially if the cooling system is poorly maintained. Factors such as low coolant levels, faulty thermostats, or malfunctioning water pumps can contribute to this problem.

The cooling system removes excess heat from the engine. If this system is neglected, the engine can overheat. Specifically, low coolant levels or a malfunctioning thermostat can both hinder heat removal, leading to overheating.

A faulty water pump, responsible for circulating coolant, can also disrupt heat dissipation. Regular checks and maintenance of these elements can prevent overheating, ensuring the truck's durability.

2. Tire Blowouts

Heat expands the air inside tires, leading to increased pressure and risk of overinflation. Overinflated tires, especially on hot road surfaces, are more prone to punctures and blowouts due to their rigidity and inability to adapt to road variations.

The added heat also impacts the tire's tread. As temperatures rise, the adhesive bonding the tread to the tire can degrade, potentially leading to tread separation. This not only hampers the tire's traction but also heightens the blowout risk.

To mitigate these risks, regular inspections for tread wear or separation are essential, ensuring early identification and rectification of potential problems, and consequently reducing the likelihood of tire-related mishaps.

3. Battery Failure

In high-temperature conditions, the battery fluid in heavy-duty trucks evaporates at a faster rate. This rapid evaporation can impede the battery's ability to hold a charge and power the vehicle's systems, potentially leading to performance issues.

Moreover, the decrease in fluid levels can trigger corrosion on the battery terminals and connections. This disruption, evident as a chalky residue, interferes with electricity flow and increases resistance in the circuit, causing the battery to underperform.

Such issues, if left unaddressed, can eventually result in battery failure. Therefore, regular maintenance, including fluid level checks and terminal cleanings, is crucial to mitigate these risks, especially in hot weather. This ensures the battery remains capable of providing reliable performance.

4. Fuel System Issues

High temperatures can accelerate fuel evaporation in a truck's system, causing an excess of fuel vapor. This disrupts the system's balance and can affect fuel efficiency. As more fuel vaporizes prematurely, it cannot combust efficiently, disrupting the optimal air-fuel mixture and reducing fuel efficiency.

Furthermore, heat-induced fuel system issues can lead to engine problems, ranging from reduced power output to severe concerns like engine knocking. In extreme cases, excessive fuel vapor may even result in hazardous conditions, such as vapor lock, causing the engine to stall or not start.

Regular fuel system maintenance and inspections are critical during high heat periods to ensure optimal functioning and prevent these issues.

5. Oil Viscosity and Lubrication

Engine oil viscosity, or its thickness and flow rate, plays a critical role in lubrication. High temperatures can reduce this viscosity, thinning the oil, and diminishing its ability to lubricate engine components effectively.

Thinner oil, brought on by high temperatures, struggles to form a protective layer between engine parts. This layer reduces friction and prevents wear, but when missing, leads to metal-on-metal contact, generating more heat and speeding up component wear and tear.

This increased wear impacts engine efficiency and can lead to component damage requiring costly repairs or replacements. To ensure optimal lubrication, it's crucial to monitor engine oil, especially in high heat, and replace it as necessary. Regular oil changes and using high-heat resistant oil can maintain viscosity and engine health.

6. Cooling System

In hot weather, the cooling system in a heavy-duty truck works overtime to regulate engine temperature by absorbing excess heat and dissipating it via the radiator. Any underlying issues with the system components—radiator, coolant, hoses, or fans—become more apparent under such conditions.

The radiator is vital in this process, but if it's compromised due to leaks or blockages, its ability to cool effectively is diminished. High temperatures compound this issue, potentially leading to engine overheating. Similarly, issues with the coolant, such as low levels or contamination, and problems with hoses or fans can hamper proper heat transfer, reducing the cooling system's efficiency.

These issues are especially noticeable in hot weather as the cooling system struggles to maintain engine temperature. Regular maintenance and component replacements can safeguard the system's performance, even under extreme weather conditions.

7. Air Conditioning System

High temperatures place a substantial burden on a truck's air conditioning (AC) system, which strains to maintain a cool cabin environment. Any system deficiencies or malfunctions can severely impact the AC's efficiency and cool air output.

One key issue impacting AC performance is low refrigerant levels, the fluid responsible for removing cabin heat. Low refrigerant, caused by usage or system leaks, hampers the AC's cooling ability, leading to less cool air and potentially an uncomfortably hot cabin.

System leaks, occurring in the compressor, condenser, or refrigerant hoses, are common and more evident in hot weather. These leaks can cause a reduction in refrigerant levels and allow contaminants in, potentially causing more damage. Regular maintenance, especially before hot weather sets in, can help ensure the AC system is prepared to handle the heat.

8. Aftertreatment System

The aftertreatment system in a heavy-duty truck reduces harmful emissions to meet environmental standards. Its key elements, Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and Diesel Oxidation Catalyst (DOC), can be impacted by heat. The DPF traps and burns soot, a process affected by temperature.

Heat aids regeneration but extreme heat can damage the filter. SCR reduces Nitrogen Oxide emissions using a urea-based solution (DEF). While heat helps SCR function, excess heat can decompose DEF causing system blockages. The DOC, which oxidizes certain harmful substances, may degrade under high temperatures, decreasing effectiveness.

Maintaining optimal temperatures and regular checks for these components are critical to prevent emission violations and costly repairs.

How Can Heat Effect the Aftertreatment System?

It is important for you to know that high ambient temperatures can also affect the DPF regeneration system of your truck. The DPF regeneration system is designed to burn off the soot trapped in the filter, turning it into ash. However, in extreme heat conditions, the DPF regeneration process might be impacted in the following 6 ways:

SCR System

The SCR system uses a urea-based solution (Diesel Exhaust Fluid or DEF) to reduce NOx emissions. The DEF can freeze at temperatures below 12 degrees Fahrenheit and decompose at extremely high temperatures, impacting the SCR's functionality. 


The Diesel Oxidation Catalyst works at high temperatures to oxidize carbon monoxide and hydrocarbons into carbon dioxide and water. If the exhaust temperature is too low, it will not work efficiently. On the other hand, excessive heat can cause thermal degradation of the catalyst. 

Thermal Stress

The aftertreatment system components are made of materials that can withstand elevated temperatures. However, fluctuations between high and low temperatures (thermal cycling) can cause thermal stress, leading to cracks and component failure. 

Coolant Leaks

In some designs, the aftertreatment components are cooled by the engine's coolant. Any heat-related issue causing a coolant leak can therefore affect the aftertreatment system's performance. 

Engine Overheating

When the engine runs too hot, it can affect the exhaust temperature and pressure, disrupting the balance required for the aftertreatment system to function properly. 

DPF Regeneration

In normal operation, heat is beneficial for this process. However, excessive heat due to faulty injectors, turbochargers, or EGR systems can cause uncontrolled regeneration or even damage to the DPF

About OTR Diagnostics

OTR Diagnostics gives you the ability to force DPF regen, access detailed fault code information, monitor real-time live data, perform commands such as reset aftertreatment system and track command and fault code history, all from your mobile device. 

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