The life of a class-8 semi truck is often a long-lived one; most trucks rack up 100,000 miles per year, and it's not uncommon to see trucks with over a million miles on the odometer. But those countless miles spent on the open road can take a toll on a truck's engine, even if it's built to be far more robust than the engines typically found in ordinary passenger vehicles.
So it's not unusual to see used trucks boasting engines that have undergone an overhaul. But choosing a semi-truck with an overhauled engine can be a hit-or-miss proposition unless you have all of the facts. The following focuses on the potential benefits and drawbacks of buying semi-trucks with overhauled engines.
A Typical Overhaul
The vast majority of diesel-engine overhauls are done as a preventative step to ensure good performance and extend the life of the engine itself. When a diesel engine needs an overhaul usually depends on a variety of factors, including mileage, age, and oil-analysis results. Some engines may need a rebuild after 500,000 miles of service while others run for a million miles or more before a rebuild is needed.
Diesel-engine overhauls can range from relatively basic affairs that replace common wear items to a complete teardown, replacement, and rebuild of diesel-engine components. These components are usually included in an overhaul kit sourced from the engine manufacturer. Such kits may include:
- Pistons and associated hardware, including rings, skirts, and pins
- Cylinder head hardware, including liners, seals, and head bolts
- New gaskets for cylinder head, rocker cover, and oil pan
- Valve-train components, including rocker arms and other hardware
- Connecting rod and upper/lower main bearings and shells
- New thermostat, EGR valve, and oil-pressure regulator
Benefits of an Engine That Has a New Lease on Life
An engine overhaul performed by a reputable repair shop or factory-authorized service center can breathe like-new performance and fuel economy into an otherwise tired engine. If the original owner sells his or her truck shortly after investing in an overhaul, their loss could very well be your gain.
Buying a semi-truck that's already had its engine overhauled by the previous owner may also save you the trouble of investing in your own overhaul. According to truck expert Bruce C. Mallinson, an in-chassis engine overhaul may cost $10,000 in basic parts and $3,000 to $4,000 in labor. Purchasing a recently overhauled semi-truck could end up saving you tens of thousands of dollars while giving you several years of reliable service.
Guarantees of Quality or Longevity
On the other hand, buying a semi-truck with an overhauled engine can be a risky gamble, especially if there aren't any service records available for said engine overhaul. Without the records, chances are you won't have any idea of how long the overhaul will hold up—the engine in your new purchase could last another 500,000 miles, or it could need another rebuild at 150,000 miles.
Engine overhauls performed by independent repair shops can also vary in overall quality, since the quality of the work depends greatly on the skill level of the mechanics performing the work. Sloppy work done by an unscrupulous shop could cause your recently purchased semi-truck to have a shorter-than-expected lifespan.
There is no clear-cut answer when it comes to purchasing a semi-truck with an overhauled engine. By keeping the above pros and cons in mind, you'll be able to make a purchasing decision that best suits your trucking needs as well as your budget. Look at products from a variety of dealers to find semi-trucks that suit both your situation and your budget and will serve you well.