2.4-liter naturally aspirated GDI and 2.0-liter T-GDI are the main culprits, engines that equip 2011 to 2014 models from both South Korean automakers. In other words, you’re looking at nameplates such as the Hyundai Sonata , Kia Optima, the Santa Fe Sport, the Sportage, and the Sorento. The problem, as it happens, has been labeled as a machining error during the engine production.The error, Hyundai and Kia note, “may cause premature bearing wear within the engine.” The condition may happen as a result of metal debris that wasn’t completely removed from the crankshaft’s oil passages during the cleaning process. What’s more, it appears that the crankpins were produced with uneven surface roughness.The first sign the engine may be on its way to seize is a knocking noise coming from the prematurely worn connecting rod bearing. Left as is, the problem may lead to engine stalling at high speed, which increases the risk of a crash. It’s no wonder, then, that the two companies admitted this problem as being a serious no-no.It’s believed each automaker will spend something like 250 billion won to fix the faulty engines, working out at approximately $220 million for Hyundai and $220 million for Kia at current exchange rates. Of the 1.48 million vehicles included in this recall, 1.19 million were sold in the United States, and another 114,187 are located in Canada. Hyundai's recall campaign is programmed to begin on May 25, 2017, with Kia to follow six days later.Today’s news comes just after Hyundai announced a major operation in March. Affecting vehicles produced from 2011 to 2015, roughly one million Sonata sedans are to have their seat belt linkages inspected. One year before this campaign, the U.S.-spec Sonata was serviced for a circuit board-related problem with the power steering.