Critical failure of a car or truck’s internal systems—including its engine, brakes, or suspension—is the root cause of 44,000 crashes each year in the United States.
Preventing engine failure is vital for staying safe on the road.
It’s also cost-effective! Consider this: once an engine has died, the cost of replacing, say, a V8 starts at $4,500, at an absolute minimum.
Meanwhile, the typical diesel engine of a heavy-duty vehicle runs between $20,000-$40,000. Even an in-frame rebuild, with refurbished parts, costs between $7,800 - $17,000 for an HDV.
Yet, by comparison, the cost to prevent the most common causes of engine failure is pocket. Fixing a radiator leak typically costs under $500; replacing fuel injectors runs from $300-$900; and a regular oil change is 99% cheaper than even the lowest-end diesel engine.
Save money and stay safe with our expert guide to truck engine failure prevention.
5 Most-Common Truck Engine Problems, Explained
To prevent engine failure, understand its root causes. Then, learn how to heed warning signs.
What Causes HDV Engine Failure?
Engines typically fail due to overheating, over-aeration (too much air in the engine), or malfunctioning components in the vehicle’s internal systems. Generally, problems occur in the following five categories.
Bad Motor (Internal Engine Damage)
Internal engine damage and motor problems threaten engine function in a few ways. These include:
Abnormal detonation (pressure surge), the spontaneous, inappropriate combustion of fuel and air in the engine’s combustion chamber, post-ignition. It’s a dangerous, swift, uncontrolled pressure increase.
Underlying causes of abnormal detonation include:
Low octane fuel
Heavy engine load
Extreme compression
Improper lubrication, which increases friction and damages engine parts.
Underlying causes include:
Oil leaks
Poor quality or inappropriate oil choice
Delayed oil changes
Buildup of engine sludge and carbon deposits. It reduces different systems’ functionality and increases the risk of contamination and overheating.
Underlying causes include:
Irregular or infrequent cleaning
Delayed filter changes.
Broken, warped, or dysfunctional components, which can cause friction or heat damage to the engine.
Engine Overheat
Overheating is another common factor in engine failure. The most common underlying causes of overheating include:
Dirty or contaminated engine coolant
A leak in the radiator or coolant system
A blown gasket
Problem With Exhaust System, Electrical System, or Ignition System Components
The complex components of a truck's exhaust, electrical, and ignition systems are vital for its function. When a component breaks or loses functionality, it poses an engine failure risk. The most common types of component dysfunction implicated in engine failure include:
Catalytic converter failure
Oxygen sensor failure
Spark plug malfunction
Dysfunctional EGR valve
Faulty ignition switch
This can cause abnormal detonation due to incorrect ignition timing.
Dead battery
Notably, fluid leaks and carbon buildup can also damage these systems.
Over-Aeration (Too Much Air In Engine)
When there’s too much air in the engine, it will degrade and, eventually, fail. The most common underlying causes of over-aeration include:
MAF airflow sensor malfunction or detachment
Vacuum leaks, often due to seal/gasket dysfunction
Dysfunction or detachment of other sensors (coolant temperature, oxygen, etc.)