G4KJ engine
The G4KJ engine is fitted to 3 generation(s): Hyundai Sonata, Kia Optima.
Common problems and what to check
Engine: Hyundai/Kia Theta II (G4KD, G4KE, G4KJ)
- cylinder scoring (especially the direct-injection G4KJ)
- knocking and oil consumption
- catalytic converter debris in the cylinders
What to check when buying: knocking on a warm engine; oil consumption; cylinder borescope inspection is a must; VIN recall campaigns.
Tip: One of the riskiest engines on the used market; don't buy without a borescope inspection.