Two problems related to engine grinding noise have been reported for the 2015 Kia Motor Optima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2015 Kia Motor Optima based on all problems reported for the 2015 Optima.
Oil light began to flicker, right before the engine began making horrible grinding noises. Engine blew shortly after. Vehicle was up to date on normal scheduled maintenance.
Sounds like pieces of metal was left in the engine during the time of manufacturing and was never taken out ,the vehicle was still running, I decided to take it to get checked , the device at kia of essington of philadelphia said it was a grinding sound on the bottom end of the engine.