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Regular maintenance is a fact of all vehicle ownership. Changing your oil every 3 to 5 thousand miles, replacing tires, or doing a timing service on a higher mileage vehicle. Car owners will encounter these things while racking up miles on their commutes or trips. If a car engine has been neglected throughout its life, there is a chance you’ll be in for more repairs than expected. Sometimes, a complete engine replacement is required. If you find yourself needing a new engine, how do you determine if it is worth replacing?

How does an engine work?

Engine Repair shop
Engine Rebuilding | Getty Images

Many internal combustion engines work by converting the heat of burning gasoline into energy that drives a crankshaft. Moving pistons up and down inside the engine cylinders, connected to the crankshaft, spinning the transmission, and then turning the wheels. Manufacturers have created engines ranging from one cylinder to 16 cylinders. Most road-going cars today will have engines ranging from the standard four-cylinder up to 10 and 12 cylinders for luxury or supercars.

Your standard car engine goes through a specific cycle: combustion, intake, compression, and exhaust. Combustion is what drives the piston downwards, pushing on the crankshaft. Intake pulls air into the cylinder through the valves along with a gasoline mixture. The mixture is then compressed, and what remains in the cylinder is expelled through the exhaust system. This is the basic process for nearly every internal combustion engine.

Symptoms of a failing engine and how to spot them

Engine Code Scanner in shop
Engine Code Scanner | Getty Images

With a solid understanding of how an engine works now comes the knowledge of when it is not working how it should. If you were to have a heart problem, there would be signs of needing to go to a doctor before more serious issues appear. The same goes for a car engine, where there is usually a sign that things are failing before catastrophe strikes. If you notice any of the following issues, it is best to take it to a shop.

  • Check Engine Light: On your dashboard, a yellow indicator light will pop up if something is wrong with the engine. If the light is solid, it should be addressed but not immediately. On the other hand, if the light is flashing, it should be looked at right away. You can use a code scanner for the check engine light, which gives you more information on the problem. It could be something as simple as a spark plug replacement.
  • Knocking or Grinding Noises: When an engine is starved of oil which lubricates all the moving components, it creates an immense amount of heat and will cause premature wear to the parts inside. However, catching it quickly can save you from complete engine failure or “blowing up” an engine.
  • Increased Exhaust or Major Leaks: Aside from condensation on a cold morning, the exhaust shouldn’t be visibly coming from the tailpipe. Excessive white smoke could mean coolant is leaking into the combustion chamber. On the other hand, an excessive amount of blueish-tinted smoke means you are burning oil in the combustion chamber. Large puddles of oil or coolant also indicate that a significant seal needs to be replaced before the system becomes dry.

Replacing a Car Engine: Is it worth it?

NASCAR engine swap with Brian Scott
Brian Scott NASCAR Engine Swap | Getty Images

If the engine has been neglected, or the signs of failure have been missed, it is necessary to replace it entirely. In most cases, J.D. Power expects you will spend as much as $4,000 for a four-cylinder and upwards of $10,000 for a high-performance engine. However, if your goal is to save some money, the engine can be rebuilt with new parts.

Another option would be to seek out a salvage engine, but you could run into issues as you don’t always know the condition. So is it worth it to replace an entire engine? The decision comes when the car engine cost exceeds the car’s value. In the eyes of insurance, this means the car is now totaled. However, it is always worth replacing if you have an attachment to the vehicle.


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