Why Can the Crankshaft Be Turned When Water Enters the Engine?
2 Answers
When water enters the engine and the crankshaft can be turned, do not rotate the crankshaft immediately. First, check the condition of the water ingress. If the engine has only mixed with water vapor entering through the air filter, the issue is not severe at this stage. Symptoms of Water in the Engine: The breather pipe becomes overheated, which can damage lubrication in summer and cause overheating. However, hot air should escape through the breather pipe of the crankcase. Engine stalling during driving occurs because the air filter element is soaked with water, increasing intake resistance and allowing water to enter the combustion chamber. The spark plugs fail to ignite, and water entering the distributor cap disrupts normal ignition function, leading to the car stalling while driving. Severity of Water in the Engine: If the engine has only mixed with water vapor entering through the air filter, the issue is minor and can be resolved with simple measures, such as cleaning the water vapor from the air filter, throttle valve, and cylinders. If more water has entered the engine but does not affect normal driving, though the engine noise is louder, it may indicate small amounts of water in the oil or fuel. In this case, replacing the engine oil and cleaning related engine components is necessary.
This is actually quite an interesting question. The last time I encountered a water-submerged car, the crankshaft could still be turned because after water entered the engine, it didn't immediately fill all the cylinders. When the piston was in the first half of the compression stroke, some water could still be squeezed out through the exhaust valve. Moreover, the connecting rod might not have been completely seized at the moment of water ingress, so with manual force, although the resistance from the water was significant, the torque from the gear set was just enough to barely turn it. However, don't think that just because it can be turned, everything is fine. Water is incompressible, and forcibly turning it can easily deform the connecting rod or even bend the crankshaft. My advice is not to experiment on your own after water submersion; it's safest to tow it directly to a professional repair shop for a cylinder inspection.
