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How much does a diesel engine rebuild cost?

Maintaining your trucks is essential to operating a successful transportation business. If a truck breaks down while in transit, you could end up spending far more than you would’ve to complete required maintenance and inspections on it, not to mention you might hurt your relationship with your customers. 

So, how much does a diesel engine rebuild cost, and is it better to get a replacement? We’ll answer these questions and more to help decide the best course of action for your business.

How much does it cost to rebuild a diesel engine?

Rebuilding a semi truck engine will often cost between $20,000 and $40,000. In comparison, replacing a truck engine generally costs $40,000-$50,000 so there are certainly cost savings in trying to repair what you have instead of just replacing it. 

But you’ll need to weigh the semi truck engine rebuild cost against the longevity of the vehicle, the ongoing maintenance costs for keeping an older truck, and much more. Choosing between a new engine and rebuilding your old one can be challenging, especially if you aren’t sure where the money will come from to complete this crucial work.

Using free online calculators can help determine if rebuilding or purchasing a new engine fits best into your budget based on your current operating capacities.

What you need to know about rebuilt engines

Before you decide that rebuilding your truck’s engine is the right move, read up on key considerations for rebuilt engines. You should have a firm grasp on what a rebuilt semi truck engine is like, what’s involved in the process, how it compares to a new engine, and more.

What does it mean to rebuild an engine?

If you’re rebuilding an engine for the first time, you should take time to learn the steps involved.

  • Remove the engine block from the truck and fully disassemble every piece.
  • Clean and inspect each piece as you evaluate the engine’s condition.
  • Replace any damaged parts with new parts that meet OEM standards. Parts that often need to be replaced include piston rings, seals, bearings, gaskets, and lubricants that have worn out. Some people prefer to preemptively replace all these parts regardless of their wear because it will improve performance. You should only replace larger pieces like the crankshafts when necessary.
  • Next, you’ll recondition the internal surfaces of the cylinder and head gasket to ensure a strong seal with the rings.
  • Reassemble the engine block and place it back into the vehicle.

Once you’ve completed this process, your engine is like new. It can last as long as a new engine would, only you’re benefiting from a lower repair cost, being more eco-friendly because you aren’t putting your old engine in a junkyard or landfill, and knowing the health of every piece of your truck’s engine.

Does rebuilding an engine make it new?

Rebuilding an engine does not necessarily make it new. You won’t replace every part of the engine as that would get costly and make the repairs not worth the expense in comparison to replacing the engine. 

However, rebuilt engines can last as long as new engines, making it a wise move for individuals looking to save money on replacing their truck’s engine. Most importantly, a rebuilt truck engine should function like new for many years to come.

How do you know when you need an engine rebuild?

Before an engine goes out, you’ll see some telltale signs that something isn’t quite right. These signs include:

  • More smoke than normal coming from the tailpipe
  • Knocking sounds under the hood
  • Burning oil at a faster rate
  • Engine overheating

When you have a good commercial mechanic who does regular maintenance on your truck, they should be able to tell you when you need to start thinking about rebuilding or replacing your truck’s engine. And at this point, some owner operators or trucking companies look to purchase a new truck instead of repairing the old one with hundreds of thousands of miles on it.

Is it worth it to rebuild an engine?

It really depends. This is a decision you should make in conjunction with your commercial mechanic. Your mechanic can advise on the status of other areas of your truck and how many more miles you can expect to get from it. If other areas are worn out and getting close to needing to be replaced, you might not want to drop anywhere from $20,000 to $40,000 just to rebuild the engine.

You’ll need to weigh your budget with the immediate needs of your truck. Evaluate when you have budgeted for a new vehicle and don’t forget other expenses, such as increases in insurance for driving a higher-value truck.

Rebuilding an engine can be well worth it depending on the status of other truck mechanical parts. So, before you make the investment, be sure you’ve weighed the long-term benefit and ongoing maintenance expenses for your older truck.

How long do semi truck engines last?

Most semi truck engines last about 750,000 miles when properly maintained. However, the frequency at which you idle your truck will significantly impact the total mileage that you get out of your vehicle. 

5 reasons you should consider a rebuilt engine

Rebuilding your engine will breathe new life into your existing truck. That can help you get the most out of your original investment to optimize your expenses and maximize your bottom line.


Rebuilding an engine is not cheap. In fact, the final price can be close to the total cost of a new engine. But it is far less than it costs to purchase a new truck. 

You can finance your truck engine rebuild. Talk to your mechanic about their financing options or look into other business loans that can help cover these expenses. You can also sell your outstanding invoices to a factoring company to get money fast but without the traditional loan process.


As you consider whether to rebuild your engine, purchase a new engine or opt for an entirely new truck, evaluate the cost of the pieces needed to rebuild your engine. 

The first step in a rebuild is to take the engine apart and evaluate each piece. Once you’ve done this, you can determine with your mechanic what parts need to be replaced. 

Using OEM parts will provide a better long-term experience with your vehicle so it’s best to invest in high-quality materials for your rebuilt engine.

Once you know the extent of the parts required for the rebuild, you’re ready to make an informed decision about how to handle your truck maintenance requirements.

Proven track record

Your existing engine might be one of the best out there. In that case, newer is not always best. Evaluate the longevity and quality of the engine you have. If it’s a good one, you might more heavily consider rebuilding it instead of purchasing a replacement.

And at this point, you know what to expect with this engine. These can be some benefits of moving forward with a rebuilt engine.


Rebuilding an engine takes time. And that can mean staying off the road for several days or even weeks while your mechanic completes the work. For some owner-operators or small transportation companies, having a truck out of commission for that long is not realistic.

Even though you might save some money on rebuilding the engine instead of replacing it, the cost of not being able to use your truck during this time might make it not worth the time away from work and lost ability to make money.

Older can mean simpler 

Older rigs are often simpler to maintain. And with that comes another benefit – lower labor expenses and lower costs for parts. Newer vehicles tend to have more advanced electronics and other features that make them costlier to maintain and can mean there is more that can go wrong with these vehicles.

Rebuilding a diesel engine vs engine overhaul

Rebuilding an engine is more thorough than a diesel engine overhaul. With a rebuild, you’re taking the entire engine apart and reviewing all materials for wear, and determining whether they need to be replaced. In the end, you should have an engine that is just like new!

With an engine overhaul, you’re replacing worn-out items but not necessarily disassembling the entire engine. It’s possible that you could experience more engine problems just a few miles down the road since the parts replacement is on an as-needed basis and less pre-emptive than an engine rebuild.

Now you may be asking, is it cheaper to rebuild or replace an engine? Rebuilding may be cheaper in the long run versus the potentially lower short term diesel engine overhaul cost.

Engine rebuild: Big savings if you can spare the time

Ultimately, an engine rebuild is a great way to elongate the life of your semi truck, provided you can spare the time it takes for your mechanic to complete the work with high-quality results.


How much does it cost to recondition a diesel engine?

It can cost $2,000- $10,000 to recondition a diesel engine depending on the make, model, age, and what specifically needs reconditioning. A full rebuild is generally more expensive than addressing a few minor issues that may restore performance.

Is it worth rebuilding a diesel engine?

Rebuilding a diesel engine can be worth it if the engine has a lot of wear but the core components are still functional. This is often cheaper than replacing the whole engine and can restore performance. However, if the block itself is cracked or components like the crankshaft are damaged beyond repair, a full replacement may be a better option.

How much does it cost to overhaul an engine?

An engine overhaul typically costs between $3,000-7,000 for parts and labor, depending on factors like engine type, shop rates, parts pricing, and whether it’s a basic rebuild or a performance build. More extensive overhauls with upgraded internals and custom machine work can run over $10,000.

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