Is It Cheaper to Rebuild a Truck Engine or Replace It?

Heavy-duty trucks are designed not only to run for years but to run for years on a demanding schedule, hauling the loads that keep America running. Many of them will enter into the seven-digit mileage club before needing to be retired or having any major rebuilding done. Even smaller diesels can go hundreds of thousands of miles before needing serious rehabilitation. 

However, the mileage will eventually take its toll on every component of your truck, and there’s no component that works harder than your engine. No matter how rigid you are with maintenance and repairs, there will come a time when your engine will start to display some of the signs that signal the end of its useful life. 

At this point, you’ll likely need to decide if you’re going to rebuild the engine or replace it entirely. We’re going to dig into what exactly a rebuilt engine is, and how it compares to a new one. We’ll also talk about when you might want to rebuild, and when you may want to replace the engine or even the whole truck. Read on to learn about the signs that may point to needing to replace your engine, as well as where you can turn to get it done with professionalism and transparency.


How Much Does It Cost to Buy vs. Rebuild an Engine?

The actual cost of a rebuilt engine compared to a new replacement engine will depend on many different factors.

The first is what specific engine needs to be installed. Heavy-duty trucks require heavy-duty engines, and these engines are not cheap. New engines can cost anywhere from $3,000 up to nearly $10,000. Rebuilding most engines will cost a fraction of that unless major machining work needs to be done. 

No matter which option you choose, you’ll still need to pay the labor on the removal and reinstallation, which can take anywhere from 10-30 hours to complete. For the rebuild, you’ll also need an additional labor cost component to reflect the time it takes the technician to perform the rebuild of the engine after its removal. 


Costs Involved in Engine Rebuilds

There are some factors that can affect the overall cost of the engine rebuild. There are many potential rebuild kits available from various manufacturers, each with a price that reflects the components in the kit. There are kits to replace original equipment parts, and there are kits and parts designed to improve performance or otherwise customize the engine performance. Diesel engines are incredibly complex and as such, there are many different parts that are involved in rebuilds. 

The parts that are often needed include:

  • Valve-train components
  • Timing components
  • Cylinder head springs, rockers and other hardware
  • Connecting rod
  • Bearings 
  • Pistons
  • Rings
  • Skirts
  • Pins
  • Thermostats
  • EGR valves
  • Oil pressure regulator
  • Gaskets 
  • Seals 


When to Replace vs. Rebuild Your Truck’s Engine

The most important thing to consider before making any decision about whether to rebuild or replace your engine is what the actual failure diagnosis was. In some cases, your mechanic may find that a more simple repair is needed. Otherwise, once their assessment is complete they will be able to tell you if a rebuild or a replacement is a better option.


When It’s Best to Rebuild

Rebuilding an engine can be a far more cost-effective solution to getting your rig back on the road than full engine replacement. It can often take just as long to complete and can leave you with the original engine your truck came in with. 

This means your electronic control unit (ECU) won’t need hundreds or even thousands of miles to recalibrate, and you are also minimizing part waste by reusing some of the same major components like the block and heads. 

There are some extreme cases when the cost of the potential rebuild will be more than a new engine, but this typically only occurs with a catastrophic engine failure or significant block damage. 

Pros of rebuilding your engine include:

  • Far lower cost than replacement
  • Extends the life of the existing engine
  • Reduces part waste and scrap by reusing core components
  • Full ECU and transmission compatibility


When It’s Best to Replace

There are very few cases where it’s going to be more economical or otherwise desirable to completely replace the engine, but they do exist. One possibility is that when the engine failed, it was damaged enough that a rebuild either isn’t possible or isn’t feasible. 

This can happen when there is significant damage to the block, like a crack between cylinders, which generally cannot be reliably repaired. Damage like this can often happen when an internal component breaks and damages the engine internally.

Pros of replacing include:

  • Brand new engine with factory tolerances
  • All new components
  • Potentially lower labor cost


Is a Rebuilt Engine as Good as a New Engine?

In many cases, especially those where the rebuild is performed by a trusted, local shop with extensive experience in rebuilding heavy-duty diesel engines, the rebuilt engine will be no different than a new one. In some cases, it may perform even better. Engines that are rebuilt by skilled technicians can add several hundred thousand miles to the lifespan of the engine core.

However, this isn’t to say that all rebuilt engines are as good as new ones, and in some cases, they can be worse. Since diesel engines operate at such significant compression ratios and low tolerances, rebuilds done by unskilled or inexperienced technicians can result in significantly shorter potential lifespans. In cases of significant inexperience, damage to the transmission or countless other systems can occur as well. 


When Should I Get My Engine Checked?

Initially, you should stick to the maintenance schedule laid out by the manufacturer. This schedule will often be accelerated based on various usage factors, including what type of environment the truck is primarily operated in and the conditions under which it is operated. 

Additionally, you should have your engine checked out anytime one of the dashboard lights indicates there may be an issue. Lights such as “check engine” may seem like lazy, catch-all lights, but they can help prevent more serious problems when addressed promptly.


Telltale Signs of Engine Problems

While many people will tell you they’ve had an engine failure with notice, this is rarely true and, in most cases, the engine will give you plenty of notice. This is especially true for truckers, who tend to be more in tune with the performance and operation of their machines than the average daily commuter. Here are some of the common signs that your engine is having problems and may need repair, rebuilding, or replacement. 

  • Spun Rod Bearing – A spun rod bearing is one of the most significant failures that can happen to a diesel engine. The bearing seizes and often causes the connecting rod to break and damage the engine internals. This is often the result of significant use without adequate lubrication.
  • Lost Oil Pressure – If your engine has a fuel or coolant leak in a bad spot, it can lead to contaminated oil, which leads to a higher oil level. This usually means that the fluid is leaking into and out of the engine, and so the engine must be dismantled to find the leak.
  • Significant Blow-By Blow-by is where your fuel-air mixture leaks past the piston seals and gets into the crankcase. Blow-by is an issue because it creates high crankcase pressure, and reduces overall power. Blow-by is often seen as a high volume of white smoke in the exhaust.
  • Dropped Valve – A dropped valve is a common failure in a diesel engine, and is the term for when a valve head bends or breaks off into the cylinder. This can lead to incredible damage to the cylinder, piston and valve systems. 
  • Consuming Oil or Coolant If your engine has been consuming coolant or oil at an increased rate, it could be a sign that something is wrong with one of the seals. It can result from several sources, with common ones being cracked cylinder heads, blown head gaskets and damaged cylinder liners.
  • Your Fuel Efficiency is Waning When you’ve put a lot of miles on your truck, you know what kind of mileage you can expect with just about any type of load imaginable. If you start to notice your fuel efficiency dropping at an accelerated rate, it may be the right time to have your engine looked at.


Repair Your Truck’s Engine Today

Blaine Brothers are ready to be your trusted local engine repair resource. No matter what your needs are for diagnostics, service or repairs, we can help you meet those needs with professionalism, experience and attention to detail. We know your truck is your livelihood, so we make a concerted effort to keep you in the loop at every point in your truck’s repair. 

If your truck is having performance issues while on a haul, if you’ve had a “check engine” light come on recently, or if you just want to get a once-over of your truck for better insight into its health, reach out to Blaine Brothers today, and let us know what you need!

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