One problem related to crankcase (pcv) has been reported for the 2018 Kia Motor Optima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2018 Kia Motor Optima based on all problems reported for the 2018 Optima.
Consuming fuel to the amount of roughly 1/2 quart per 150 miles. Vehicle has been inspected by mechanic and the oil pan, oil filter, and pcv valve has been replaced and engine oil uv dye added and cycled with no leaks found. The risk is that if not rigorously checked often, the engine will malfunction because the car runs out of oil. I have had my mechanic checking this car since I purchased it in January 2026. We have had to replace the oil pan and do two full oil changes with three separate quarts of oil being added in between all of that to keep it topped up. My mechanic agrees that the engine is consuming oil at an extremely high rate. My mechanic and a mechanic at the dealership where I purchased it are the only one who has inspected the car for this issue so far. The mechanic at the dealership is who recommended we replace the oil pan to see if that fixed the leak, which my personal mechanic did. Yes the critical engine failure lamp illuminates on the dashboard when the oil ran out the first time while I was driving it. This was how I discovered that there was an oil leak. This specific incident occurred three weeks after I purchased the car which I bought in mid-January of 2026.