Updated 4 October 2026. This is general information for owners, not legal advice. The class action websites linked below are the authoritative source.
The short answer: two class actions are running in the Federal Court of Australia over alleged defects in Hyundai and Kia four-cylinder petrol engines. On 19 August 2026 the Court allowed the claims to be expanded, and vehicles with Nu MPI engines (codes starting G4NA, G4NB and G4NH) are now included. The eligibility period was also extended to vehicles bought or leased up to 24 August 2026. If you were told earlier that your car was not covered, it is worth checking again.
What changed in 2026
- 19 August 2026: the Court granted leave to file amended statements of claim that set out the alleged defects in more detail and expand the class.
- Nu MPI engines added: engine codes beginning G4NA, G4NB and G4NH are now included.
- Eligibility period extended: it previously ended on 15 February 2023. It now covers affected vehicles bought or leased after 1 January 2011 and before 24 August 2026, whether new or second hand.
- 6 November 2026: Hyundai and Kia have until this date to file amended defences.
- 10 February 2027: the next case management hearing.
Sources: hyundaiengineclassaction.com.au and kiaengineclassaction.com.au, checked 4 October 2026.
Which engine codes are covered?
The class actions are defined by engine family. Your engine code is stamped on the block and printed on the compliance plate; our engine codes guide shows where to find it.
| Engine family | Codes starting with | Common Australian models |
|---|---|---|
| Theta II MPI | G4KD (2.0), G4KE (2.4), G4KG (2.4) | ix35, i45, Sonata, Sportage SL, Cerato TD, Sorento XM |
| Theta II GDI | G4KJ (2.4), G4KH (2.0 turbo) | ix35, Santa Fe, Sonata, i30 N, Optima, Sportage QL, Sorento |
| Gamma GDI | G4FD (1.6), G4FJ (1.6 turbo) | Accent, i30, Veloster, Tucson 1.6T, Kona 1.6T, Rio, Cerato GT, Seltos 1.6T |
| Nu GDI | G4NC (2.0) | i30, i40, ix35, Tucson TL, Cerato YD, Sportage SL, Rondo |
| Nu MPI (added August 2026) | G4NB (1.8), G4NA (2.0), G4NH (2.0) | i30 GD 1.8, Elantra, Kona 2.0, Veloster 2.0, Cerato, Seltos 2.0, Sportage QL 2.0, Soul |
Model years matter, and not every variant of each model is covered. Use the full vehicle tables on the official sites to confirm yours.
What is not covered
Diesel engines and six-cylinder engines are not currently part of either class action. That means the iLoad and iMax D4CB diesel and the Carnival 3.3 V6 are outside it.
What the claims allege
In broad terms the claims allege that the affected engines have defects that can lead to increased wear, engine damage or engine failure. Hyundai and Kia deny the allegations, apart from limited groups of vehicles that they say were recalled and rectified. Nothing has been decided by the Court.
These are the same failure patterns we see in the workshop: bottom-end knock on Theta II engines, and oil consumption followed by bearing wear on Nu engines. Our guides to G4KJ engine problems and Nu engine problems (G4NB and G4NC) describe the symptoms.
What to do if you own an affected car
- Confirm your engine code and model year against the tables on the official class action site for your brand.
- Register your interest on that site. If you registered before, you do not need to do it again.
- Check for open recalls on your VIN. Recall repairs are done by dealers at no charge. See our Hyundai and Kia recalls guide.
- Keep your records: purchase paperwork, every service invoice, and any dealer correspondence about oil use or engine noise.
If your engine has already failed
The class action websites ask owners with a recent serious engine failure to contact them, because an inspection of the vehicle may help. So before the engine is repaired or replaced:
- Email the class action team first and ask what evidence they need.
- Ask your dealer whether a recall, warranty or goodwill repair applies. You also have rights under the Australian Consumer Law consumer guarantees, which are separate from the manufacturer’s warranty.
- Do not let the old engine disappear. Reconditioned engines are normally sold on a changeover basis, which means your failed engine goes back to the supplier as a core. If you are a group member, tell your workshop before the swap so the failure can be photographed and described on the invoice, and ask the class action team whether the engine needs to be kept.
- Get an itemised invoice showing the engine code, the failure found and what was replaced.
You do not have to wait for the case to finish to get your car back on the road. A reconditioned engine supplied and fitted commonly costs between $4,500 and $7,500 depending on the model. See Hyundai engines for sale, Kia engines for sale, or the cost guides for the i30, Tucson and Sportage.
Hyundai and Kia engine class action FAQs
Is there a Hyundai and Kia engine class action in Australia?
Yes. Two separate class actions are running in the Federal Court of Australia, one against Hyundai (NSD 131 of 2023) and one against Kia. They allege defects in certain four-cylinder petrol engines sold in Australia since 1 January 2011. Hyundai and Kia deny the allegations, other than for limited groups of vehicles they say were already recalled.
Which engines are included?
Theta II MPI (G4KD, G4KE, G4KG), Theta II GDI (G4KH, G4KJ), Gamma GDI (G4FD, G4FJ), Nu GDI (G4NC) and, since August 2026, Nu MPI (G4NA, G4NB, G4NH).
Are diesel engines included?
No. Diesel engines and six-cylinder engines are not currently covered, so the iLoad D4CB diesel and the Carnival V6 are outside the class actions.
I bought my car after February 2023. Am I included?
Possibly. The eligibility period was extended in August 2026 and now covers affected vehicles bought or leased after 1 January 2011 and before 24 August 2026, new or second hand.
Can I still get my engine replaced if I am part of the class action?
Yes. Being a group member does not stop you repairing your car. Tell the class action team before the work is done, and keep the invoice, the failure description and your service history.
Engine already failed? Call 03 9630 0960 or use the quote form with your rego or VIN. We will confirm the engine code, tell you whether it is one of the affected families, and price a tested reconditioned replacement with a 12-month warranty.
