This restriction could “result in a vehicle stall, increasing the risk of a crash.” The problem seems to stem from worn engine parts essentially degrading over time, and flaking off pieces of metal.
That metal is said to float around the engine oil pan and could, as stated above, collect enough to restrict the oil flow and starve the engine to the point of stalling.
Hyundai has already issued a recall on the 470,000 cars affected, and has told customers the cars can be brought to the dealers for inspection, and if necessary, the company will replace the faulty engines at no cost. The recall is only for the 2.0 liter and 2.4 liter engines that come in the Sonata.
While the NHTSA doesn’t go into what to do if your car does stall, we felt it necessary to give a brief what-to-do if you encounter this situation. While driving down the road, the NHTSA states that the faulty engine “will produce a metallic, cyclic knocking noise from the engine” and then stall out.
If the car stalls, calmly shift the car into neutral, turn the engine off, and then back on again, at that point you’ll be able to steer to the side of the road and come to a stop, reducing the risk of an accident. The key though is remaining calm.