Is Replacing the Four-Matching Parts Considered a Major Overhaul?
2 Answers
No. Generally, the concept of a major overhaul refers to the replacement of the four-matching parts of the vehicle's engine and the grinding of the crankshaft with matching bearings. The four-matching parts include the piston, piston rings, cylinder liner, and piston pin. Grinding the crankshaft refers to thinning the crankshaft and then installing larger matching bearings. Here is additional information: Four-Matching Parts: The four-matching parts consist of the cylinder liner, piston, piston rings, and piston pin. Disassembling the piston connecting rod assembly is relatively simple—just loosen the connecting rod bolts and remove the lower connecting rod bearing cap to extract the piston connecting rod assembly from the cylinder. Before disassembly, be sure to mark each connecting rod and observe the front and rear directions of the piston.
Replacing the 'four-piece set' is considered a major engine overhaul. With over a decade of experience in the auto repair industry, I've encountered many such cases. The so-called 'four-piece set' refers to core components like pistons, piston rings, cylinder liners, and valves. Replacing them requires completely disassembling the engine for inspection. This process is not only time-consuming—taking at least one or two days, sometimes up to a week—but also costly, averaging around three to four thousand yuan. Ignoring minor faults can lead to worsened oil burning or even complete engine failure. I recommend car owners regularly check engine oil and coolant levels, and change the oil promptly to effectively prevent major overhauls. Additionally, after replacement, the engine needs a break-in period—avoid high speeds for the first few hundred kilometers, just like with a new car, to extend its service life.
