How to Determine if a Small Amount of Water Has Entered the Engine Intake?
3 Answers
Here are methods to determine if water has entered the engine: Check the engine oil condition: Normal engine oil colors include light yellow, brown, or transparent colorless, but it generally should not appear milky white. Use the dipstick to check for any milky white oil-water mixture. If present, it indicates water has entered the engine. Inspect the air filter: Check the air filter and the lower housing for obvious signs of water ingress. Examine the intake pipe and intake manifold for clear traces of water passing through. White smoke from the exhaust pipe: When there is water in the engine fuel or combustion chamber, the water is heated by the combustion heat in the cylinder, turning into steam that exits through the exhaust pipe, forming white smoke. If white smoke appears after the vehicle has driven through water, it is highly likely that water has entered the engine.
Last time I drove through a puddle after the rain at a bit higher speed, the engine seemed to cough a little when starting, and after starting, the idle was unstable with the tachometer jumping around, making a sputtering sound. I stopped the car, turned off the engine, opened the hood, and pulled out the spark plugs to find water traces on the electrodes, with small water droplets on the inner wall of the intake pipe—clearly, water had been sucked in. With a small amount of water intake, the engine can still run but with great difficulty. If you continue to drive hard, the water compressed in the cylinder can damage the piston rod, leading to costly repairs. It's advisable to pay attention to the starting time and operational vibrations after driving through water, and check if the air filter is wet if necessary. Drive slowly through puddles to avoid splashing water high—prevention is better than cure.
I find it quite interesting to ponder this while playing with cars. Judging the symptoms of a small amount of water intake isn't complicated: for example, the engine takes longer to start, the car shakes violently after starting, the RPM fluctuates, or the exhaust pipe emits some white smoke. The checks you can do yourself are simple: park the car, pull out a spark plug to see if the electrode is wet with rust marks; use your phone's flashlight to check the intake pipe for water droplets. A small amount of water might allow you to limp along, but don't push your luck—water compression can spike cylinder pressure, which is risky. Drive slowly through water to reduce intake flow. If you notice anything unusual, don't gamble—stop immediately and have it towed for professional inspection to avoid engine failure.
