Performing routine maintenance, such as regular oil changes and recommended services, keeps a car engine running smoothly and helps prevent costly repairs. But car owners don’t always follow all the manufacturer’s guidelines on how often to perform those services, which could damage the engine. Sometimes the engine malfunctions and the car owner may not recognize the problem or may wait too long to have it addressed, causing even more issues. If engine damage goes too far, the entire engine may need to be replaced. This article outlines just how costly that kind of repair can be.
How Does an Engine Work?
Before digging into this significant expense, it’s important to outline how an engine works. The engine is the heart of the car, truck, or SUV. The vehicle’s full function is dependent upon the engine, and if it isn’t running, or running well, it has a massive effect.
Inside of almost every modern internal combustion engine (ICE) are pistons, which move up and down inside of cylinders. These move up and down to spin the crankshaft. The crankshaft is then connected to the car’s drivetrain (which include its transmission, drive shaft, and CV axles) to turn the car’s wheels, providing forward and backward motion.
Combustion is what causes the up and down motion of the pistons, in a process that looks like this:
- As the piston moves downwards in the cylinder, the intake valve(s) open(s), and the vacuum created by the piston’s motion pulls the air/fuel mixture in. Or if the engine has direct injection, the valves let in the air while the injector sprays an adequate amount of fuel to match.
- As the piston moves back up the cylinder, the valves close, the air/fuel mixture is compressed, ignited by the spark plug, and this sends the piston back down.
- The next time around, the exhaust valves open, and as the piston moves back up, it pushes the spent exhaust gases out of the cylinder.
- The process then repeats.
There are many crucial components that work with the pistons as they move up and down in the engine. Here is a breakdown:
- Metallic bearings are seated between the crankshaft’s surface and bottom part of the piston. A thin layer of pressurized oil is created to ensure the most efficient motion, as well as to avoid catastrophic wear to all associated components.
- Metallic bearings sit between the engine block—which is essentially the engine rotating assembly’s housing—and crankshaft, again ensuring smooth efficient motion.
- Across the engine block are all kinds of different seals: The head gasket sandwiches between the block and cylinder head (where the valves live), the output shaft seal (or, rear crank seal) prevents engine oil from leaking out of where the crankshaft connects to the transmission’s components, and many other seals ensure engine oil doesn’t leak.
- The cylinder head has many small components that operate the valves, but the rotation of the crankshaft is what runs them all via a timing chain or belt, which is perfectly in sync to facilitate efficient overall operation.
When a Failed Component Could Lead to Replacing the Engine
There are many instances where a failed engine component could lead to an overall failure of the engine itself. Here are three of them:
- If the aforementioned piston’s lower bearings—referred to as rod bearings—fail, it could cause a major lack of oiling, allow too much movement from the piston, and lead to catastrophic internal damage.
- If the engine somehow goes out of timing, such as due to a failed timing chain tensioner or snapped timing belt, this could cause piston-to-valve contact, potentially rendering the entire valvetrain useless, damaging the block, or even putting a hole in the block.
- If the engine doesn’t have adequate oiling—whether due to not having enough, a failed oil pump, or oil that’s well past its replacement interval–a slow, gradual increase in friction will cause the engine to eventually machine itself to death, overheat, and display other instances of total failure.
Signs of a Failing Engine
The following signs could point to an engine that is on its way out:
- Reduced performance. An engine that feels particularly sluggish and returning significantly reduced fuel economy could indicate that it’s near death.
- Knocking. If a loud knocking noise is heard from the engine, which increases in beat as the revs increase, this is a bad sign.
- Grinding. A loud grinding noise could indicate a substantial increase in friction, thus it may explode or lock up.
- Increased exhaust fumes. If the exhaust produces a significant amount of white or blue smoke, this is a sign that something is wrong inside the engine.
- Major oil or coolant leaks. While a leak doesn’t necessarily mean the engine is near death, it could mean something major is wrong and eventually lead to engine damage.
How Much Does It Cost to Replace an Engine?
The exact cost of replacing an engine varies, based on different factors, including the manufacturer brand, engine displacements, and types of engines.
A typical engine replacement could cost between $2,000 and $10,000, depending on make, model, age, availability, labor cost, and other crucial factors. This range may skew higher for luxury vehicles and high-end sports cars.
Here are a few specific examples of factors that may vary the cost of an engine replacement:
- If the engine failed due to a manufacturer defect within the warranty period, there may be no out-of-pocket costs for the car owner.
- It may cost less money to replace the engine in a 12-year-old BMW than a two-year-old Honda, simply because the BMW’s engine was produced for a much longer amount of time and supply is greater than demand. Honda owners may also choose to install a lightly used engine in very good condition from a junkyard obtained for a bargain price.
- If an engine is turbocharged and the engine fails due to a lack of oiling, this means that the turbochargers also experienced a lack of oiling. Therefore, they should be replaced as well.
- An engine may be able to be reconditioned and rebuilt; however, depending upon the complexity of the engine, it may be cheaper to buy a replacement unit from the manufacturer and save on the labor needed to rebuild it.
- Some manufacturers allocated a lot of resources to producing replacement engines. One example is Mazda with its Renesis rotary engine. This lives under the hood of its 2004-2011 RX-8 sports car, and due to an abnormal amount of failures, replacements became relatively inexpensive and easy to obtain.
Summary
A car’s engine is its heart. If it fails, it could mean major mechanic work to replace, thus costing a lot of money. There are many ways engines can fail and require replacement, so it’s important to take good care of them, follow service intervals closely, and keep an eye and ear out for anything out of the ordinary happening under the hood.
