Price based on changeover. Fitting available at extra cost.
🛡️
12-month warranty
On all engines
Free shipping
Australia-wide
🔧
Expert fitting
Dandenong workshop
🏆
10+ years exp.
Hyundai & Kia
The Kia Optima G4KJ is a reconditioned 2.4L GDI petrol engine, supplied from $5,999 with a 12-month product warranty and free Australia-wide shipping. Fitting is available at our Dandenong workshop.
| Engine code | G4KJ |
|---|---|
| Capacity | 2.4L |
| Fuel system | GDI petrol |
| Engine family | Theta II |
| Condition | Reconditioned & tested |
| Fits | Kia Optima, Sportage & Sorento; Hyundai Sonata, Santa Fe, Tucson & Grandeur |
| Warranty | 12 months |
| Delivery | Australia-wide |
Looking for a reliable replacement Kia Optima G4KJ engine? Hyun Engines supplies professionally tested and quality-assured G4KJ 2.4L GDI petrol engines for Kia Optima and selected Hyundai-Kia vehicles throughout Australia.
The G4KJ engine is part of Hyundai and Kia’s well-known Theta II engine family and combines strong performance with excellent fuel efficiency. Featuring Gasoline Direct Injection (GDI), Dual CVVT technology and a timing chain-driven DOHC design, the G4KJ engine delivers smooth power and responsive driving performance.
Whether your original engine has suffered from bearing damage, excessive oil consumption, engine knocking, overheating, low compression or complete engine failure, our replacement G4KJ engines provide a cost-effective solution to restore your vehicle’s performance.
Every engine undergoes professional inspection and testing before dispatch to ensure quality and reliability.
✔ Genuine G4KJ 2.4L GDI petrol engine
✔ Professionally inspected and tested
✔ Reliable replacement solution
✔ Excellent power and fuel economy
✔ Australia-wide freight available
✔ Workshop installation available
✔ 12-month product warranty included
✔ Hyundai & Kia engine specialists
The G4KJ engine offers excellent performance but, like all modern engines, can develop issues over time.
Common symptoms include:
If your Kia Optima is experiencing any of these issues, replacing the engine may be more economical than carrying out a complete rebuild.
The G4KJ 2.4L GDI engine is commonly fitted to selected:
Compatibility may vary depending on VIN number, production year and vehicle specification.
Please contact our team with your VIN number before ordering to ensure the correct engine is supplied.
Hyun Engines specialises in Hyundai and Kia replacement engines. Our experienced team understands the Theta II engine platform and can help identify the correct replacement engine for your vehicle.
We supply engines to workshops, mechanics, dealerships and private customers throughout Australia.
Every engine is tested and inspected before dispatch to help minimise downtime and provide dependable long-term performance.
We can arrange freight delivery throughout Australia, including:
Contact us today for stock availability, freight pricing and delivery estimates.
A 12-month product warranty is included for additional peace of mind.
Our team can assist with:
| Engine Code | G4KJ |
| Engine Capacity | 2.4L |
| Fuel Type | Petrol |
| Fuel System | GDI (Gasoline Direct Injection) |
| Engine Family | Hyundai Theta II |
| Configuration | Inline 4 Cylinder |
| Valve Train | DOHC 16 Valve |
| Variable Valve Timing | Dual CVVT |
| Timing System | Timing Chain |
| Condition | Reconditioned (tested) |
| Warranty | 12 months |
The G4KJ is a 2.4L four-cylinder petrol engine from Hyundai and Kia's Theta II engine family. It features GDI fuel injection, Dual CVVT technology and a timing chain-driven design.
The G4KJ is a GDI (Gasoline Direct Injection) engine.
The G4KJ engine is commonly fitted to selected Kia Optima 2.4L petrol models depending on production year and market specification.
Common issues include connecting rod bearing wear, excessive oil consumption, timing chain noise, overheating and engine knocking.
Yes. Every engine is professionally inspected and tested before dispatch.
Yes. Warranty options are available. Contact us for current warranty information.
Yes. We regularly deliver engines throughout Australia.
Yes. Professional installation services are available.
Simply provide your VIN number and our team will verify compatibility before purchase.
In many situations, replacing a severely damaged engine with a tested replacement engine can be quicker, more economical and more reliable than a full rebuild.
Other reconditioned Hyundai & Kia engines from our workshop.




Hyun Engines
🕐 Mon–Fri 9am–5pm · Sat & Sun closed
Mon–Fri, workshop hours
We reply quickly
VIC 3175, Australia
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