How Many Times Should the Engine Oil Be Changed After Water Ingestion?
4 Answers
Engine oil should be changed twice after water ingestion. Below are detailed explanations regarding the engine: Definition: An engine is a machine capable of converting other forms of energy into mechanical energy. Internal components include: Internal combustion engines (reciprocating piston engines), external combustion engines (such as Stirling engines, steam engines, etc.), jet engines, electric motors, etc. For example, internal combustion engines typically convert chemical energy into mechanical energy. The term 'engine' can refer to both the power generation device and the entire machine including the power unit (such as gasoline engines, aircraft engines).
After my car went through water, I noticed the engine oil had emulsified, so I immediately had it towed to the repair shop. The mechanic explained that when water enters the engine, the oil turns milky white and requires thorough cleaning. The first oil change is a basic step to drain the water-contaminated old oil. However, one change usually isn't enough because residual moisture can hide in the corners of the crankcase. During the repair, they recommended two oil changes: after the first cleaning, start the engine and let it run for ten minutes to mix the remaining moisture with the new oil; then perform a second complete replacement to ensure safety. In severe cases of water ingress, a third oil change might be necessary to guarantee system cleanliness. During this process, they also checked the spark plugs and cylinder for rust, and the whole repair took three days.
After the last heavy rain, my car was flooded, and the engine stalled directly. The mechanic shook his head after opening it up, saying the piston rods were bent, and the repair cost over 8,000 yuan. The key point is that the engine oil must be changed repeatedly. First, drain the water-contaminated oil and flush the oil pan. The first batch of new oil can only run for a few dozen kilometers before turning cloudy. Then, change it a second time, replacing the oil filter and cleaning the fuel lines. Finally, during the third oil change, a specialized cleaning agent was circulated for half an hour before the oil dipstick returned to its normal color. Don’t try to save money by changing the oil just once—residual water molecules can cause bearing rust, potentially leading to a major engine overhaul.
The experienced mechanic at the repair shop told me that the number of oil changes after engine water ingress depends on the severity. For mild water ingress, change twice: first to drain the emulsified oil and clean the oil passages; add new oil and idle the engine before the second change. For severe water ingress, three changes are needed, with each interval including 30 minutes of operation to allow residual water to mix with the oil. The key is to replace the oil filter simultaneously with each oil change, and the oil pan must be removed for thorough cleaning. Otherwise, metal debris will circulate with the new oil, causing secondary damage. The interval between oil changes should not exceed 50 kilometers, and after the final change, check the oil's clarity.
