2021 Kia Sportage: Theta II Engine Knock and Connecting Rod Bearing Failure

The failure mechanism is a connecting rod bearing that loses its oil film and wears until it hammers against the crankshaft journal. On Theta II GDI engines this has been attributed to a combination of manufacturing debris in the oil passages on earlier builds and, on all of them, sensitivity to low oil level and extended change intervals. By the 2021 model year the manufacturing side had been addressed, which is why this is a far smaller problem here than on a 2013 Sorento — but the engine's sensitivity to oil starvation is architectural and did not go away.

• The early warning is a rhythmic knock or tapping that increases with rpm, most audible at idle in an enclosed space or with the hood open.
• It is often preceded by rising oil consumption, which is why the two issues on this vehicle are connected rather than separate.
• Kia has deployed a Knock Sensor Detection System software update that monitors for the vibration signature of bearing wear and puts the engine into a reduced-power limp mode before it seizes. Verify this has been applied.
• Extended engine warranty coverage has applied to many Theta II vehicles. Terms differ by model and model year, so ask a Kia dealer to check the VIN specifically rather than relying on general reporting.
• A check engine light with the vehicle suddenly limited to low power is what a knock sensor detection trigger looks like from the driver's seat.

Practical protection: change the oil every 5,000 miles rather than 7,500, check the level monthly, and keep every receipt. Kia has required maintenance documentation when evaluating engine warranty claims.