Does a car need to clean the internal oil passages of the engine?
3 Answers
Engine oil passages need to be cleaned. If you haven't finished running the engine at high speeds yet, you can wait until after the first maintenance to do so, and then perform an engine oil passage cleaning during the next maintenance. Additionally, engine cleaning should be done every time you perform maintenance. Below is some additional information: 1. Consequences of not cleaning the engine: If the engine is not cleaned, once it becomes clogged, it will affect the engine's performance. The dirt left on the internal parts of the engine will increase wear and tear on the engine components, leading to insufficient oil pressure, which can cause valve noise and engine sounds, thereby affecting the engine's lifespan. 2. Formation of carbon deposits: Due to the characteristics of electronic engine control, each time the cylinder operates, fuel is injected first before ignition. When the engine is turned off, the ignition is immediately cut off, but the fuel injected during this cycle cannot be recovered and instead adheres to the intake valve and combustion chamber walls. The fuel evaporates easily, but the wax and gum substances in the fuel remain. Over time, these substances accumulate and thicken, hardening upon repeated heating and forming carbon deposits.
I recently researched this issue, and the conclusion is quite interesting. The engine oil passages are like human blood vessels - new cars don't need deliberate cleaning, but it's different for older vehicles with over 100,000 kilometers. Especially for engines that have been repaired after problems or used low-quality oil for long periods, sludge buildup can truly block small oil holes. When I once disassembled an engine, the sludge adhering to the oil passage walls was thicker than soot on a pot bottom, making oil flow impossible. If symptoms like abnormal cold start noises or slow oil pressure light illumination appear, it might really need cleaning. There's now a dynamic cleaning method that doesn't require disassembly - just add cleaner to the old oil, let it idle for half an hour, then replace with new oil and filter. But remember to find professional shops, as amateur attempts might flush sludge into bearings causing bigger trouble.
Last week during maintenance, I was asked if I wanted this service. Honestly, for regular family cars with proper maintenance, it's unnecessary. As long as you change genuine engine oil and filters on time, the internal oil passages of the engine can generally stay clean. However, there are two exceptions: first, frequently delaying oil changes—I've seen engines that went 30,000 km without an oil change, with the oil pan full of sludge when opened; second, turbocharged cars that burn oil, where carbon deposits can travel past the piston rings into the oil pan. The effectiveness of oil passage cleaning is quite questionable. Unless the oil pressure gauge shows abnormalities or there's obvious sticking in the hydraulic valve lifters, it's not worth spending the money. If you really want to maintain your car better, shortening the oil change interval is a more cost-effective approach.
