Is Visual Carbon Deposit Cleaning Inside the Cylinder Necessary?
4 Answers
Visual carbon deposit cleaning inside the cylinder is necessary. Below is the relevant introduction to visual carbon deposit cleaning inside the cylinder: 1. Cleaning with detergent: Engine detergent is used to remove carbon deposits inside the engine. Generally, for not severe cases, it can achieve good cleaning results. If the carbon deposit is severe, it is recommended that the owner adopts the method of uncovering the cylinder head to clean the valves and cylinder walls. At this time, the operation will be relatively more complicated, so it is suggested that the owner chooses a guaranteed professional 4S store and asks professionals to clean it. 2. Do not use inferior oil: It is necessary to avoid using inferior or fake "three-no" lubricating oil. If inferior oil is used, over time, it will not only fail to achieve the purpose of cleaning the engine carbon deposits but may even damage the engine. Therefore, it is recommended that the owner usually goes to a formal repair shop for maintenance, which is more guaranteed.
Visual cleaning needs to be evaluated case by case. During my last maintenance, the mechanic showed me the inside of the cylinders with an endoscope—the carbon deposits had clumped into chunks. For older cars with 70,000-80,000 kilometers, where excessive carbon buildup on piston tops affects compression ratio, cleaning is indeed effective. But for new cars or those that recently had carbon removal, it's unnecessary—over-cleaning can damage the cylinder wall coatings. The key is the endoscope inspection results: if carbon deposits exceed 3mm thickness or develop crack patterns, treatment is needed. There's now a method using chemical soaking plus suction, combined with endoscope guidance for precision, which can reduce fuel consumption by about 5% post-cleaning. However, be cautious if a repair shop pushes cleaning without even having inspection equipment.
As someone who frequents repair shops, honestly, visual cleaning is just a routine upgrade in tools. In the past, blind cleaning was like sweeping the floor with your eyes closed, but now using an endoscope is like turning on a flashlight. Especially for direct injection engines, you can see the fuel injectors clogged with carbon deposits after just 20,000 to 30,000 kilometers. At this point, pressurized chemical cleaning works particularly well. But be careful not to fall for scams: some shops use cheap cleaning solutions that leave a lot of residue, which can clog the catalytic converter. I recommend using fuel tank additives for daily maintenance—if carbon buildup isn’t severe, there’s no need for drastic measures. If you really need cleaning, choose a reputable shop with camera-equipped devices and compare the before-and-after images on the spot to ensure it’s done properly.
Owners who just had their engine decarbonized last week, share your experience. My car with 60,000 km on the odometer always shook during cold starts. The mechanic showed me with a borescope—the piston tops were as black as a pot's bottom! The full visual cleaning cost over 400 yuan. The process was quite interesting: first, the cleaning agent was injected into the cylinders to soak, then the borescope probe went in, showing the solution bubbling and dissolving the carbon deposits, and finally, the extracted liquid was all black. The most noticeable change after cleaning was the reduced engine roar during acceleration, and the displayed fuel consumption dropped from 9.2 to 8.6. However, the mechanic said for a lightly commuted car like mine, the next cleaning could wait until another 50,000 km.
