What should you do when driving through flooded roads?
Experts advise that when driving on flooded roads and experiencing engine failure, drivers should not attempt to restart the engine but should call for roadside assistance.
According to the National Center for Meteorological and Hydrological Forecasting, due to the impact of Typhoon No. 2, on July 23rd and 24th, moderate to heavy rain and thunderstorms are expected in the Northeast, Northwest, and Hanoi regions, with some areas experiencing very heavy rain. Heavy rain will cause flooding on some roads, making travel difficult and potentially leading to vehicle breakdowns.
Automotive experts advise that if a road is flooded and unsafe, drivers should avoid it and choose an alternative route. They should also avoid driving next to large vehicles or near oncoming traffic, as these vehicles can create waves that easily cause water to enter the engine compartment. Drivers should also turn off the air conditioning and drive in a low gear.
According to Ngo Duy Ngoc, a traffic rescue worker in the Mai Dich area (Nam Tu Liem, Hanoi), if a vehicle stalls while driving through flooded areas, drivers should not attempt to restart it as this can lead to hydrolock, resulting in very high repair costs. Therefore, drivers, even those with high ground clearance, need to be very careful when driving through flooded areas.
According to automotive engineer Le Van Tach, when driving into flooded areas without knowing the depth, drivers should slow down to avoid water suddenly entering the engine, which could cause hydrolock, bending, or breaking of the connecting rod.
According to Mr. Tach, if driving slowly in deep water, the engine will stall automatically. In that case, the driver should absolutely not attempt to restart the engine but should call for roadside assistance. If the driver tries to restart the engine, the intake system will continue to operate, and the pistons will be pushed up very quickly by the crankshaft to continue the air compression process. However, the amount of water entering the combustion chamber will exert a huge force in the opposite direction. These two forces will deform the connecting rod.
"At best, the connecting rod will bend and the cylinder wall will be scratched; at worst, the connecting rod will break, leading to a puncture in the cylinder wall, destroying the engine and incurring very high repair costs. Vehicles that drive through flooded areas need to go to garages to have the air filter, air intake, and air-fuel mixture checked and cleaned to prevent water from entering the combustion chamber and causing the engine to stall," engineer Le Van Tach advised.
Hydraulic lock is a phenomenon where water enters the combustion chamber of the cylinder through the air intake while the engine is running, causing the piston to become blocked and preventing fuel from burning in the combustion chamber, leading to engine stalling.
Compared to gasoline engines, diesel engines are more susceptible to hydrolock and more severe damage because diesel engines have a higher compression ratio and a smaller combustion chamber, so even a small amount of water entering the engine can cause hydrolock.
