Is it cleaner to change engine oil by draining or suction?
3 Answers
Changing engine oil by draining is the cleaner method. The reasons are: The drain plug is located at the lowest point of the oil pan, which allows almost all the engine oil to be drained out. At the same time, you can visually observe the condition and color of the old oil during the draining process, which helps in assessing the engine's working condition. The sediment and impurities at the bottom of the oil pan can also be drained out, and the metal shavings attached to the drain plug can be cleaned in time, avoiding contamination of the new oil. Information about oil change is as follows: 1. Lift the vehicle, remove the underbody guard, and loosen the drain bolt on the oil pan. This is a common method for oil change, but the disadvantage is that the draining time is longer, and there may be some residual old oil left in the oil pan. 2. The suction method uses vacuum gas to create suction. The suction tube of the suction device is inserted into the oil pan through the oil dipstick to extract the oil. This method is faster, and most engines will have very little old oil remaining.
Back when I was young and working on cars, I often pondered this issue. When changing oil, draining it out is usually cleaner—why? Because when you unscrew the oil pan bolt, gravity helps all the oil flow out, including the sludge and metal particles settled at the bottom. Some vehicle oil pans even have magnets specifically designed to trap these impurities, which are removed during the draining process. While oil extraction is quite convenient—no need to lift the car, just pump through the dipstick tube—the suction tube might not reach the deepest parts, leaving some old oil behind. Over time, this can affect the performance of the new oil. Unless the vehicle model is special or the tools are too basic, I recommend prioritizing the draining method. For regular maintenance, develop a habit of changing oil periodically. Don’t let dirty oil burden the engine—keeping it running smoothly can also save you money on fuel.
As a DIY car owner, I find oil extraction can be cleaner and more convenient in certain situations. From my experience, extracting oil eliminates the need to crawl under the car—just draw it directly through the dipstick tube, saving time and effort while preventing messy oil spills. With professional-grade equipment and strong suction, you can achieve thorough oil removal, especially for European models with complex oil pan designs. However, traditional draining has its merits too, like allowing all contaminants to flow out smoothly. I recommend choosing based on your vehicle's usage—oil extraction works great for urban commuter cars as it's simple and efficient. Never skip routine maintenance; changing oil early prevents carbon buildup, extends engine life, and reduces repair visits.
