How Much Does It Cost to Rebuild a Jeep 4.0 Engine?

The cost to rebuild a Jeep 4.0 engine can vary depending on several factors, such as the repair shop’s location, the engine’s condition, and the specific parts that need to be replaced.

Generally, the cost for a basic rebuild with standard parts can range from around $1,500 to $3,000. However, the cost can increase significantly depending on the parts used and the extent of the rebuild and it can easily go beyond $5,000.

Rebuilding an engine can include a variety of different tasks and costs. Here are some common tasks and associated costs that may be included in rebuilding a Jeep 4.0 engine:

ItemDescriptionAverage Cost
PartsPistons, bearings, gaskets, seals and additional cost$500 – $5000
LaborDisassembling, cleaning, reassembling, testing and tuning the engine$40 – $100/hour
Machine workResurfacing cylinder heads or engine block$500 – $1000
Additional costsFluids, paint, and miscellaneous items$100 – $200
4.0 Inline-Six Jeep Engine in a 1994 ZJ

Parts ($500 to $5,000)

The cost of parts will vary depending on what specific parts need to be replaced but can include pistons, bearings, gaskets, and seals, similar to the cost of rebuilding a Ford 302 engine. These parts can cost anywhere from a few hundred to several thousand dollars.

These include:

  • Pistons ($50 – $150 each). The cylindrical parts that move up and down in the engine’s cylinders. They are responsible for compressing and expanding the fuel-air mixture.
  • Bearings ($20 – $100 each). These components allow the engine’s moving parts, such as the crankshaft and camshaft, to rotate smoothly.
  • Gaskets ($10 – $50 each). The seals that prevent oil, fuel, and other fluids from leaking out of the engine.
  • Seals ($5 – $20 each). The components seal the engine’s oil and other fluids, preventing leaks.

Other parts may also need to be replaced depending on the engine’s condition, such as the connecting rods, valves, and timing chain/belt. The cost of these parts can vary greatly depending on the specific part and the supplier and if you are using new or used parts.

Here is a rough estimate for additional parts:

  • Connecting Rods ($50 – $200 each)
  • Valves ($20 – $50 each)
  • Timing Chain/Belt ($50 – $200)

Some parts may be more expensive than others, for example, if the engine has suffered severe damage, the cost of the parts may be higher.

PartsAverage Cost
Pistons$50 – $150 each
Bearings$20 – $100 each
Gaskets$10 – $50 each
Seals$5 – $20 each
Connecting Rods$50 – $200 each
Valves$20 – $50 each
Timing Chain/Belt$50 – $200

Labor ($50 – $100/hour)

The labor cost for each of the tasks included in rebuilding an engine can vary depending on the engine’s specific engine model, the engine’s condition, and the mechanic’s or auto shop’s labor rate.

Labor costs include

  • Disassembling the engine ($40 – $80/hour). This involves removing all the parts from the engine block, such as the pistons, bearings, and gaskets.
  • Cleaning the engine ($40 – $80/hour). This includes cleaning all the engine parts to ensure they are free from dirt and debris.
  • Reassembling the engine ($70 – $150/hour). This involves installing all the new or refurbished parts and ensuring everything is properly aligned and tightened.
  • Testing and tuning the engine ($40 – $80/hour). After the engine is reassembled, it needs to be tested to ensure it is running properly and any necessary adjustments are made.

Also, some shops may charge a flat rate for the whole rebuilding process, it’s recommended to get quotes from multiple mechanics or auto shops to compare prices and ensure you’re getting a fair deal.

Labor Average Cost per hourAverage Cost in total
Disassembling$40 – $80/h$50 – $150
Cleaning$40 – $80/h$50 – $150
Reassembling$70 – $150/h$200 – $500
Testing and tuning$40 – $80/h$50 – $150

Machine work ($500 – $1000)

Some engine parts may need to be machined or ground to fit properly, similar to the process when rebuilding a 6.7 Cummins engine. This could include resurfacing the cylinder heads or the engine block, which can add to the cost. This process can also be time-consuming and require specialized equipment and skilled labor.

The machine work cost can vary greatly depending on the specific engine model, the engine’s condition, and the mechanic’s or auto shop’s labor rate.

Machine work costs may include:

  • Resurfacing ($200 – $500) Refinishing the surface of parts such as cylinder heads or engine blocks to ensure they are smooth and flat. This is typically done by using a machine that uses a grinding or milling process.
  • Boring ($300 – $800) This process increases the cylinder bore size to fit larger pistons.
  • Honing ($200 – $500) This process is used to smooth and finish the cylinder bore.
  • Decking ($200 – $500) This process ensures that the cylinder head and engine block have a flat surface for proper gasket sealing and compression.
  • Line boring ($500 – $1000) This process ensures that the main bearings and connecting rod bearings are properly aligned with the crankshaft.

Some shops may combine different machine works into one flat rate. Unless you’re doing the work yourself, check with a few shops to see where you can get the best deal.

Machine costsAverage cost
Resurfacing$200 – $500
Boring$300 – $800
Honing$200 – $500
Decking$200 – $500
Line boring$500 – $1000

Additional costs ($100 – $200)

Additional costs may include fluids, paint, or other miscellaneous items. These costs are usually minor and may include new hoses, belts, and other small parts that may need to be replaced during rebuilding.

These are

  • Fluids ($50 – $100): Oil, coolant, transmission fluid, power steering fluid, and other fluids that may need to be replaced during rebuilding.
  • Paint ($50 – $100): Any painting that may need to be done on the engine or other parts to protect against rust and corrosion.
  • Other miscellaneous items ($50 – $100): Small parts such as hoses, belts, and other items that may need to be replaced during rebuilding.
Additional costsAverage cost
Fluids$50 – $100
Paint$50 – $100
Other miscellaneous items$50 – $100

Note: The above cost estimates are approximate and may vary depending on the specific parts, labor rates, and location.

As you can see, the cost of rebuilding a Jeep 4.0 engine can vary widely depending on the specific circumstances, so it’s important to get a detailed quote from a mechanic to get a better idea of the cost for your specific situation.

A replacement engine may be a more cost-effective option if the engine is beyond repair, similar to the considerations when rebuilding a Harley engine.


How many work hours are needed to rebuild an engine?

The number of work hours needed to rebuild an engine can vary greatly depending on the engine model, the engine’s condition, the mechanic’s or auto shop’s skill level, and how detailed you want to get. It can take 40 to 60 hours, depending on these factors.

How to tell if the engine is worth rebuilding?

If the engine has a solid block and crankshaft, is free from excessive wear, and has not suffered major damage, it may be worth rebuilding. A reputable mechanic or engine builder can evaluate the engine’s condition and advise whether rebuilding is a good option.

How long will a rebuilt engine last?

A well-done rebuild with high-quality parts can potentially last as long as a new engine, which is typically around 150,000 to 300,000 miles, or even longer with proper maintenance and care. However, the lifespan of a rebuilt engine can be much shorter if the rebuild is not done properly, or if the engine is not maintained properly after the rebuild.

  • Alex

    Alex is the founder and driving force behind the blog you're reading. As a lifelong spender with a keen eye for making informed financial decisions, he's dedicated to analyzing the economy and digging deep into online data for valuable insights. With a passion for sharing financial wisdom, he equips readers with practical advice and useful tips for a better financial future. In his free time, Alex enjoys the outdoors and a good book.