How to Tell if the Engine Has Taken in Water

[StZoey]

If the water level reaches above half of the wheel, there is a possibility that the engine has taken in water. Check the air filter for obvious signs of water ingress, and inspect the intake pipe and intake manifold for any water traces. When you pull out the dipstick, uncontaminated engine oil appears as a translucent, shiny liquid, whereas oil mixed with water will appear opaque, brown, or yellowish. Remove the spark plugs from each cylinder and check if they are wet. If they are, it indicates signs of water entering the engine.

[Jess]

That day I worked on a flood-damaged car where the owner had driven into standing water and stalled. Here are some practical tips: First, pop the hood and check the air filter—if it's soaked like a freshly washed foam sponge, it's likely water got in. Then pull out the dipstick to inspect the oil; normal oil is clear amber, but after water intrusion, it turns milky like white tea—just like the flood car I saw last week. The most obvious sign is excessive dripping from the exhaust pipe, and when starting, the exhaust makes a chugging sound like it has asthma. A reminder: never force a start! Last week, a owner tried to restart after stalling in water and ended up bending a piston, costing over 8,000 in repairs.

[JourneyFitz]

Veteran drivers say the exhaust pipe tells the most straightforward story. When the engine runs normally, the exhaust emits faint white smoke. If water gets in, the smoke becomes extremely thick with a misty quality, like the smoldering smoke from wet firewood. The tachometer also acts up—stepping on the gas won’t raise the RPM, and the engine wheezes like someone who just finished a marathon. My neighbor once noticed a damp, fishy smell in the cabin after driving through water, and lifting the floor mats revealed muddy water stains underneath. Nowadays, repair shops have a moisture-detecting pen that plugs into the spark plug hole to measure cylinder humidity with over 90% accuracy.

[LaMarley]

Auto Mechanic's Perspective Reveals Professional Detection Methods. Remove the spark plug and use a borescope to inspect the cylinder walls—water ingress leaves obvious water stains. Blow compressed air into the spark plug hole; you'll hear bubbling sounds if water is present. Pull out the crankcase ventilation tube and sniff—water-contaminated oil smells like rust mixed with river water. The most accurate method is measuring cylinder pressure: normal readings range from 9-12 bar, but post-water ingress, it often drops below 5 bar. However, regular car owners are advised against DIY disassembly, as improper handling may cause cylinder block damage.