G4NA

Knocking on a cold start that fades when warm, rising oil consumption, low compression; a borescope shows vertical scoring

Russian specialist press calls cylinder scuffing the main fault of the G4NA, sometimes before 100,000 km. The aluminium open-deck block has thin cast-iron liners that go oval with hard use or overheating, and ceramic dust from a failing catalytic converter scores the bores. A Moscow workshop rebuilt a 2017 Sportage at 142,000 km with scored cylinders and pistons (bored to the single +0.50 mm oversize, new pistons). Piston-cooling oil jets and coated bearings arrived in 2017; engines from 2019 are reported as better. In the US, Hyundai recalled 2019-2021 Elantra, Kona and Veloster with a related 2.0 Nu MPI for oil rings that scuffed the bores (NHTSA 21V-301). Cost not sourced.

Oil level dropping between services, blue smoke, oil-level warning

The thin oil-control rings lose tension and stick, often by 60,000-80,000 km according to two Russian specialist publications; a workshop teardown found coked oil rings. The factory allows up to 600 g of oil per 1,000 km. Change the oil about every 7,500 km and check the level often.

Rattle from the exhaust, catalyst efficiency code, loss of power; later cold-start knock if debris has scored the cylinders

The ceramic core of the close-coupled catalyst rarely survives past 100,000 km (Za Rulem), and its dust is drawn into the cylinders and scores them. A workshop traced scored bores on a 2017 Sportage to a crumbled upper catalyst. Post-2019 engines got new ECU software and catalysts. Replacing a failing catalyst early protects the engine. Cost not sourced.