✓ In stock 🚚 Free shipping
🔄 Changeover basis
Reconditioned Engine
Kia Optima G4KJ Engine 2.4L GDI Petrol Engine
Original price was: $7,500.00.$5,999.00Current price is: $5,999.00. You save $1,501.00
Price based on changeover. Fitting available at extra cost.
✓Reconditioned engine — fully tested
✓12 months product warranty
✓Free shipping across Australia
✓10 years in business — trusted seller
✓Fitting available at our Dandenong workshop
ℹ
What is changeover? Send us your old engine core when you receive ours. This keeps your cost low.
12-month warranty
On all engines
Free shipping
Australia-wide
Expert fitting
Dandenong workshop
10+ years exp.
Hyundai & Kia
- Free Shipping in Australia
- Reconditioned engine.
- 12 Months Product Warranty
- 10 Years in Business, Trusted Seller
- Deal is based on Changeover
- Fitting available at Extra cost
- Engine is not include any accessories.
Kia Optima G4KJ Engine for Sale Australia
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.Why Choose Our Kia Optima G4KJ Engine?
✔ 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 ✔ Warranty options available ✔ Hyundai & Kia engine specialistsEngine Specifications
| Specification | Details |
|---|---|
| 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 | Tested Engine |
| Warranty | Available |
Common Kia Optima G4KJ Engine Problems
The G4KJ engine offers excellent performance but, like all modern engines, can develop issues over time. Common symptoms include:- Engine knocking noises
- Excessive oil consumption
- Connecting rod bearing wear
- Timing chain noise
- Low compression
- Engine overheating
- Check engine light warnings
- Reduced performance
- Internal engine damage
Vehicle Compatibility
The G4KJ 2.4L GDI engine is commonly fitted to selected:- Kia Optima
- Kia Sportage
- Kia Sorento
- Hyundai Sonata
- Hyundai Santa Fe
- Hyundai Tucson
- Hyundai Grandeur
Why Buy From Hyun Engines?
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.Australia-Wide Delivery
We can arrange freight delivery throughout Australia, including:- Melbourne
- Sydney
- Brisbane
- Adelaide
- Perth
- Canberra
- Hobart
- Regional Australia
Warranty & Technical Support
Warranty options are available for additional peace of mind. Our team can assist with:- VIN compatibility verification
- Engine identification
- Installation advice
- Technical support
- Freight arrangements
Frequently Asked Questions
What is the G4KJ engine?
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.Is the G4KJ engine GDI or MPI?
The G4KJ is a GDI (Gasoline Direct Injection) engine.Which Kia Optima models use the G4KJ engine?
The G4KJ engine is commonly fitted to selected Kia Optima 2.4L petrol models depending on production year and market specification.What are common G4KJ engine problems?
Common issues include connecting rod bearing wear, excessive oil consumption, timing chain noise, overheating and engine knocking.Do you test the engine before sale?
Yes. Every engine is professionally inspected and tested before dispatch.Does the engine come with warranty?
Yes. Warranty options are available. Contact us for current warranty information.Can you ship Australia-wide?
Yes. We regularly deliver engines throughout Australia.Do you offer installation services?
Yes. Professional installation services are available.How do I confirm compatibility?
Simply provide your VIN number and our team will verify compatibility before purchase.Why should I replace rather than rebuild my engine?
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.- Condition: Reconditioned
- Warranty: 12 months
- Basis: Changeover
- Shipping: Free Australia-wide
- Fitting: Available at Dandenong workshop (extra cost)
- Accessories: Not included
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- Free shipping Australia-wide on all engine orders
- Dispatch within 2–3 business days of order confirmation
- Changeover core must be returned within 14 days of delivery
- Fitting available at Dandenong workshop — call (03) 9630 0960
- Returns accepted — see our returns policy
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📍 Visit our workshop in Dandenong
Hyun Engines — Grand Autoworks
📍 8 Hammond Rd, Dandenong VIC 3175
🕐 Mon–Fri: 8am–5pm
Sat: By appointment
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Serving
Melbourne & Victoria
Specialising in
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Workshop
Dandenong VIC 3175
After the car was purchased with an unknown engine issue that turned out to be serious, my Kia Optima ended up being towed straight to Hyun Engines. They found the issue immediately and gave me a realistic recommendation. They fitted a reconditioned G4KJ 2.4L engine and delivered the car back in five days. The difference is immediately noticeable — smooth, quiet and responsive. This is the workshop you want when something serious goes wrong with your engine.
After the timing chain stretched and caused serious internal damage, I got my Kia Optima into Hyun Engines. They found the issue straight away and gave me a fair assessment. They sourced a reconditioned G4KJ 2.4L and had it fitted in five days. The Kia Optima runs like new and I’ve put serious kilometres on it since. Wouldn’t hesitate to recommend Hyun Engines to any Hyundai or Kia owner.
Brought my Kia Optima to Hyun Engines after the water pump failed causing severe overheating damage. Assessment was done quickly and the quote was very competitive. They sourced a reconditioned G4KJ 2.4L and had it fitted in five days. The Kia Optima starts first turn and pulls cleanly through the whole rev range. The warranty on the engine also gave me great peace of mind.
My Kia Optima had engine seized after a slow oil leak went unnoticed and I wasn’t sure it was worth saving. The team were honest about what was needed and didn’t try to upsell anything. They installed a reconditioned G4KJ 2.4L engine and completed a full check in four days. Back to being the reliable daily driver it was before the failure. Genuinely impressed with the quality, speed and honest pricing.
Didn’t know where to turn after my Kia Optima suffered carbon buildup caused a valve to fail catastrophically. Within hours they had a diagnosis and a competitive price. They sourced and fitted a reconditioned G4KJ 2.4L engine faster than I expected. The engine is smooth and quiet and I couldn’t be happier. Couldn’t fault a thing about the experience. Five stars.
After compression dropped to nothing across all four cylinders, my Kia Optima ended up being towed straight to Hyun Engines. The team had it assessed within a couple of hours and gave me a clear written quote. They fitted a reconditioned G4KJ 2.4L unit and had the job completed faster than I expected. The difference is immediately noticeable — smooth, quiet and responsive. Wouldn’t hesitate to recommend Hyun Engines to anyone with a Hyundai or Kia.
Didn’t know where to turn after my Kia Optima suffered overheated on a long drive and the engine was badly damaged. Hyun Engines went through it properly and explained exactly what had happened. They sourced a quality reconditioned G4KJ 2.4L engine and had everything fitted and running in three days. The difference is immediately noticeable — smooth, quiet and responsive. Pricing was fair and the whole experience was professional from start to finish.
My Kia Optima came in to Hyun Engines after the timing belt snapped at speed and bent multiple valves. Within hours they had a diagnosis and a competitive price. They supplied and fitted a reconditioned G4KJ 2.4L engine in three business days. The Kia Optima runs like new and I’ve put serious kilometres on it since. Couldn’t fault a thing about the experience. Five stars.
My Kia Optima came in to Hyun Engines after the timing chain stretched and caused serious internal damage. The team diagnosed it quickly and gave me a clear written quote. They sourced and fitted a reconditioned G4KJ 2.4L engine in three business days. The difference is immediately noticeable — smooth, powerful and reliable. Couldn’t fault a thing about the experience. Five stars.
My Kia Optima started burning oil heavily after 250,000km and I knew the engine was on its way out — just wasn’t sure where to take it for a job this size. A friend recommended Hyun Engines and I’m really glad he did. They assessed it, sourced a reconditioned G4KJ 2.4L engine and had the whole job done in five days. The car drives like it did when it was new and I’ve put another 15,000km on it without a single issue. The team were easy to deal with throughout and the price was genuinely competitive.
Ordered a G4KJ 2.4L engine for a Kia Optima rebuild from Hyun Engines. It arrived on schedule and the packaging was professional with proper foam protection and crating. Unboxed it at the workshop and found the engine in perfect condition, exactly as described. That kind of reliability makes a real difference when you have a customer waiting.
The Kia Optima had a failed water pump caused the engine to overheat severely and I needed it sorted fast. The team were honest about what was needed and didn’t try to upsell anything. They installed a reconditioned G4KJ 2.4L engine and completed a full check in just over a week. Back to being the reliable daily driver it was before the failure. Genuinely impressed with the quality, speed and honest pricing.
My Kia Optima started consuming oil heavily and losing compression — the kind of problem that usually ends with an expensive decision. Hyun Engines assessed it honestly and gave me a competitive quote for a reconditioned G4KJ 2.4L replacement. The job was done in five days and the car has been faultless since. What impressed me most was the transparency throughout — they showed me exactly what they found and explained every step of the repair. Highly recommended for Kia engine work in Melbourne.
Didn’t know where to turn after my Kia Optima suffered oil pressure light came on and the engine was ticking badly. Hyun Engines diagnosed it straight away and gave me an honest recommendation. They sourced and fitted a reconditioned G4KJ 2.4L and had it running perfectly in under a week. The difference is immediately noticeable — smooth, quiet and responsive. Couldn’t fault a single thing about the experience.
After the engine seized while towing and was completely written off, I got my Kia Optima into Hyun Engines. The team were honest about what was needed with no upselling. They sourced a reconditioned G4KJ 2.4L and had it fitted in four business days. The Kia Optima starts first turn and pulls cleanly through the whole rev range. The warranty on the engine also gave me great peace of mind.
Drove my Kia Optima in on its last legs after the previous owner had done a poor DIY repair that ultimately failed. They found the issue immediately and gave me a realistic recommendation. They fitted a reconditioned G4KJ 2.4L engine and delivered the car back in just over a week. The difference is immediately noticeable — smooth, quiet and responsive. This is the workshop you want when something serious goes wrong with your engine.
After detonation damage from running on the wrong fuel for too long, my Kia Optima ended up being towed straight to Hyun Engines. The team were honest about what was needed and didn’t try to upsell anything. They installed a reconditioned G4KJ 2.4L engine and completed a full check in three business days. The difference is immediately noticeable — smooth, quiet and responsive. Genuinely impressed with the quality, speed and honest pricing.
Brought my Kia Optima in after coolant mixed with oil after a head gasket failure. They found the issue immediately and gave me a realistic recommendation. They fitted a reconditioned G4KJ 2.4L engine and delivered the car back in four business days. Back to being the reliable daily driver it was before the failure. This is the workshop you want when something serious goes wrong with your engine.
My Kia Optima ended up at Hyun Engines after timing belt snapped at high revs and bent multiple valves. They found the issue immediately and gave me a realistic recommendation. They fitted a reconditioned G4KJ 2.4L engine and delivered the car back well ahead of the quoted timeframe. Back to being the reliable daily driver it was before the failure. This is the workshop you want when something serious goes wrong with your engine.
Drove my Kia Optima in on its last legs after an oil cooler failure contaminated the engine oil. Hyun Engines diagnosed it straight away and gave me an honest recommendation. They sourced and fitted a reconditioned G4KJ 2.4L and had it running perfectly in four days. The difference is immediately noticeable — smooth, quiet and responsive. Couldn’t fault a single thing about the experience.
The Kia Optima had the engine ingested road debris through a damaged air filter and I needed it sorted fast. Hyun Engines went through it properly and explained exactly what had happened. They sourced a quality reconditioned G4KJ 2.4L engine and had everything fitted and running in five days. Back to being the reliable daily driver it was before the failure. Pricing was fair and the whole experience was professional from start to finish.
Had my Kia Optima towed to Hyun Engines after spun a bearing after the oil pump failed. The team were honest about what was needed and didn’t try to upsell anything. They installed a reconditioned G4KJ 2.4L engine and completed a full check well ahead of the quoted timeframe. The difference is immediately noticeable — smooth, quiet and responsive. Genuinely impressed with the quality, speed and honest pricing.
My Kia Optima came in to Hyun Engines after the timing belt snapped at speed and bent multiple valves. They assessed it thoroughly and were upfront about the options. They sourced a reconditioned G4KJ 2.4L and had it fitted well ahead of schedule. The Kia Optima drives better now than it did before the failure. Will be coming back for all future engine work without question.
Didn’t know where to turn after my Kia Optima suffered the timing belt snapped at speed and bent multiple valves. Hyun Engines had it diagnosed within hours and gave me a realistic price. They fitted a reconditioned G4KJ 2.4L engine faster than I expected. The Kia Optima drives better now than it did before the failure. Will be coming back for all future engine work without question.
My Kia Optima ended up at Hyun Engines after piston rings wore out causing heavy blow-by and poor performance. Hyun Engines diagnosed it straight away and gave me an honest recommendation. They sourced and fitted a reconditioned G4KJ 2.4L and had it running perfectly in three business days. Back to being the reliable daily driver it was before the failure. Couldn’t fault a single thing about the experience.
Brought my Kia Optima in after engine started burning oil heavily and smoking on startup. The team had it assessed within a couple of hours and gave me a clear written quote. They fitted a reconditioned G4KJ 2.4L unit and had the job completed in three days. Back to being the reliable daily driver it was before the failure. Wouldn’t hesitate to recommend Hyun Engines to anyone with a Hyundai or Kia.
The Kia Optima had a loose con rod bolt caused internal damage that couldn’t be repaired and I needed it sorted fast. Hyun Engines diagnosed it straight away and gave me an honest recommendation. They sourced and fitted a reconditioned G4KJ 2.4L and had it running perfectly faster than I expected. Back to being the reliable daily driver it was before the failure. Couldn’t fault a single thing about the experience.
After the engine overheated and eventually blew the head gasket left my Kia Optima undriveable, Hyun Engines was recommended. Hyun Engines had it diagnosed within hours and gave me a realistic price. They sourced and fitted a reconditioned G4KJ 2.4L engine in just over a week. Back to being the reliable car it was before the failure. This is the workshop you want for Hyundai and Kia engine work in Melbourne.
Swapped the G4KJ engine into my Optima and the fitment was perfect. All the mounting points aligned on the first try and I didn’t need any modifications to get it sitting correctly. The installation was smooth from start to finish and it fired up without any issues.
My Kia Optima ended up at Hyun Engines after oil pressure dropped suddenly and the engine was badly damaged. The team explained exactly what had happened and what was needed. They fitted a reconditioned G4KJ 2.4L engine well ahead of schedule. Really impressed with how well it performs after the repair. This is the workshop you want for Hyundai and Kia engine work in Melbourne.
Had my Kia Optima towed to Hyun Engines after hydrolock from a water crossing that went deeper than expected. Hyun Engines went through it properly and explained exactly what had happened. They sourced a quality reconditioned G4KJ 2.4L engine and had everything fitted and running in four business days. The difference is immediately noticeable — smooth, quiet and responsive. Pricing was fair and the whole experience was professional from start to finish.
My Kia Optima had catastrophic failure after the timing chain stretched and jumped and I wasn’t sure it was worth saving. The team had it assessed within a couple of hours and gave me a clear written quote. They fitted a reconditioned G4KJ 2.4L unit and had the job completed in under a week. Back to being the reliable daily driver it was before the failure. Wouldn’t hesitate to recommend Hyun Engines to anyone with a Hyundai or Kia.