When there is a malfunction in the engine of a car or equipment in daily life, it can be minor repairs or major repairs,

  The price for engine overhaul ranges from $2000 to $3500, which is the price at a 4S dealership. If you go to an external repair shop, it will be cheaper, with cheaper labor and parts, but the parts are not original. Buying a new engine is only around 5000-70000 US dollars, and a major overhaul can buy about half a new one. So why is a major overhaul engine so expensive? What exactly are they repairing? Today we will talk about the issue of major repairs.

  How does' engine overhaul 'count as' major overhaul'? In fact, 'engine overhaul' has a specific definition, and it cannot be called 'overhaul' just by repairing the engine casually.

  What is the specific definition? Let's talk about it today.

  Engine overhaul can be compared to getting a very serious illness, requiring hospitalization for professional treatment, and also burning a lot of money.

  Engine overhaul is the process of disassembling and dismantling the engine, cleaning and inspecting all components, and replacing or repairing necessary parts as needed to restore engine performance.

  The main components include: crankshaft, piston, connecting rod, cylinder liner, valve assembly, etc.

  Simply put, the engine has a very serious mechanical failure and needs to be disassembled.

  A LEGO building block, completely disassembled, cleaned one by one with a cotton swab, and then reassembled for you, that's pretty much what it means.

  So what situation requires major repairs? The main criterion for determining whether an engine needs a major overhaul is the degree of cylinder wear.

  The engine burns oil, which is the most common occurrence; Due to insufficient cylinder pressure causing a decrease in power or severe shaking, it is impossible to drive normally and requires major repairs; The internal bearing of the engine is severely worn and produces abnormal noise, requiring major repairs; Under special circumstances, the valve has been pushed and requires major repairs.

  Due to various factors, the wear and tear of the mating pairs of various components will lead to a sharp decrease in engine performance.

  When the out of roundness of the cylinder reaches 0.125mm per 100mm cylinder diameter wear, or the cone wear of the cylinder reaches 0.40mm per 100mm cylinder diameter wear, it is necessary to consider a major overhaul of the engine.

  Simply put, the cylinder was originally well sealed inside, but over time, gaps have been worn out.

  The door can't be closed firmly, it's leaking air, the windows are shaking from the wind, and rainwater can be swept in. It needs to be repaired.

  For ourselves, we certainly cannot know the degree of cylinder wear, but through some fault phenomena, we can easily determine whether major repairs are needed. Mainly used for self-defense, afraid that the repair shop will pit us.

  Generally, if a domestic car travels 100000 kilometers and an imported car travels 150000 kilometers, it may need a major overhaul. If someone says they need a major overhaul after 20000 kilometers, they are just deceiving people.

  At the same time, it is necessary to make judgments based on some vehicle phenomena, such as severe power decline, high fuel consumption, engine oil burning, blue smoke, severe knocking sound, engine abnormal noise, and so on.

  In addition, the engine also needs major repairs for water ingress and soaking.

  Every year, due to rain, many cars may encounter such situations. Be extremely careful and do not light it up again when turning off the engine, as the insurance company may not compensate.

  The gap after repairing

  Although major repairs can rejuvenate the engine, its performance cannot reach a completely new state.

  The technology, component accuracy, and assembly process in the automotive repair industry cannot be compared to the original factory process, which is not very realistic.

  We have also mentioned before that the precision of engine components such as pistons and cylinder blocks varies by a few millimeters, which is about the thickness of a hair. This can already cause an impact of about 2%.

  Simply put, a overhauled engine is a bit like a human wearing a prosthetic. It can still move, but its flexibility is definitely not as good as a real hand.

  The performance of a qualified overhauled engine is approximately 90% of the original standard. This is considered qualified.

  So, is it better to replace the engine with a new one or undergo a major overhaul?

  It depends on the price of replacing the engine, as there are also many companies on the market that manufacture engines.

  Assuming that a major overhaul of the engine costs almost 3000 dollars and a replacement engine only costs near 1500 dollars, it is actually more cost-effective to replace the engine.