The Lemon Index
The 2.4 L inline-4 in the Hyundai Sonata, Kia Optima, Kia Sorento, Hyundai Santa Fe, Kia Sportage and Hyundai Tucson, model years 2010–2022. Owners filed 21,551 complaints about cars with it (matched by VIN); 51% name the engine, #3 of the 39 everyday engines we track (1 = the most).
Known issues, checked against owner complaints
Problems owners of cars with this engine name much more often than owners of the other 38 everyday engines we track (at least 1.5× the median, and 10+ complaints):
- Engine knock and seizure (rod bearings). 4,565 of 21,551 owner complaints (21%) say the engine knocked, seized or failed, against a median of 2.7% for the other 38 everyday engines we track.
My engine is making a knock sound coming from the bottom end of motor I was driving it and no warning or anything it just started knocking
2016 owner · NHTSA complaint 11775539 - Engine fires. 1,070 of 21,551 owner complaints (5.0%) were filed with a fire reported, against a median of 1.2% for the other 38 everyday engines we track.
- Oil consumption. 1,743 of 21,551 owner complaints (8.1%) mention burning or losing oil, against a median of 0.5% for the other 38 everyday engines we track.
My vehicle keeps consuming/burning oil. In between oil changes I still need to add oil
2020 owner · NHTSA complaint 11770053
What YouTube owners say Tone 0-100, higher = more praise than trouble.
Average owner tone 35/100 across 12 model years, from 103 videos about this engine and its cars (#162 of 165 engines with a YouTube study).
Most-watched videos
- Another DEAD Hyundai 2.4L Theta II Engine. Will every single one of these FAIL? 485,595 views
- Always BLOWN UP? WHY? Hyundai / Kia 2.4 Theta II G4KE Engine Teardown 476,378 views
- How to Replace Starter Motor on 2009-2014 Hyundai Sonata 2.4L – Step-by-Step Guide 400,345 views
- Hyundai Sonata 2.4 GDI - Super Comfy & Spacious | Faisal Khan 389,319 views
Counted from video titles and captions: praise words against trouble words, weighted by views. Videos only count when the title names this engine or a car that had only this engine in those years.
Cars with this engine Tap a year for that car's full report.
- Kia Sportage201120122013201420152016201720182019202020212022
- Hyundai Santa Fe2010201120122013201420152016201720182019
- Hyundai Tucson2010201120122013201420152018201920202021
- Kia Optima2011201220132014201520162017201820192020
- Kia Sorento2011201220132014201520162017201820192020
- Hyundai Sonata20112012201320152016201720182019
Model years from NHTSA VIN decoding of owner complaints. Only years we have a car page for.
Owner complaints by model year
Counts of complaints filed so far. Older cars have had longer to collect them, and popular cars draw more because more were sold: no one reports sales by engine, so there's no per-car rate. Compare the shares below instead.
By car
| Car | Model years matched | Complaints | Name the engine |
|---|---|---|---|
| Hyundai Sonata | 2011–19 | 7,633 | 43% |
| Kia Optima | 2011–20 | 4,395 | 56% |
| Kia Sorento | 2011–20 | 4,127 | 51% |
| Hyundai Santa Fe | 2010–19 | 2,305 | 60% |
| Kia Sportage | 2011–22 | 1,955 | 65% |
| Hyundai Tucson | 2010–21 | 1,136 | 49% |
“Name the engine” = the share of that car's VIN-matched complaints that list the engine as a problem area.
What owners complain about
Share of this engine's complaints that name each area (one complaint can name several).
What owners write
| Complaints that | Count | Share | Median, other everyday engines |
|---|---|---|---|
| Say the engine knocked, seized or failed | 4,565 | 21% | 2.7% |
| Say the engine stalled, shut off or lost power | 4,313 | 20% | 13% |
| Mention fire, flames or smoke | 2,294 | 11% | 3.2% |
| Mention burning or losing oil | 1,743 | 8.1% | 0.5% |
| Mention an oil leak | 447 | 2.1% | 0.5% |
| Mention a spark plug | 351 | 1.6% | 0.5% |
| Mention a misfire | 241 | 1.1% | 0.6% |
| Mention coolant loss or overheating | 232 | 1.1% | 1.2% |
| Mention a lifter, rocker or ticking | 222 | 1.0% | 0.3% |
| Mention the timing chain | 55 | 0.3% | 0.1% |
Counted from the owner's own words in each complaint (all of the car, not only the engine). A share, not a failure rate.
When problems show up
Half of the owners who gave a mileage reported the problem between 41,000 and 110,000 miles; the middle report was at 79,000 miles (11,279 complaints with a mileage).
Recalls that name this engine 8
20V100000 Feb 2020 Fuel System, Gasoline Optima 2013, 2014
Kia Motors America (Kia) is recalling certain 2013-2014 Optima vehicles equipped with 2.4L Gasoline Direct Injection (GDI) or 2.0L GDI Turbo engines. The low pressure fuel hose may deteriorate and crack over time due to heat generated within the engine compartment.
Fix. Kia will notify Owners, and Dealers will inspect the low pressure fuel hose for damage or leaking, replacing it as necessary. If no damage or leaking is found, a heat-protective tape will be installed. Repairs will be performed free of charge. The recall began June 12, 2020. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC187.
19V539000 Jul 2019 Forward Collision Avoidance Optima 2019
Kia Motors America (Kia) is recalling certain 2019 Optima vehicles equipped with Gamma 1.6L Turbo-GDI or Theta II 2.0L Turbo-GDI engines. A software error in the Forward Collision-Avoidance Assist (FCA) system may cause the braking assist function to not engage when a stationary vehicle is detected.
Fix. Kia will notify owners, and dealers will update the FCA software, free of charge. The recall began August 27, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC179.
16V705000 Oct 2016 Power Train Optima 2016
Kia Motors America (Kia) is recalling certain model year 2016 Kia Optima vehicles manufactured November 13, 2015, to April 23, 2016 and equipped with a 2.4l engine. The right front axle driveshaft may crack and fail.
Fix. Kia will notify owners, and dealers will replace the front axle driveshaft, free of charge. The recall began November 2016. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC139.
15V568000 Sep 2015 Engine Sonata 2011, 2012
Hyundai Motor America (Hyundai) is recalling certain model year 2011-2012 Sonata vehicles manufactured December 11, 2009, to April 12, 2012 at Hyundai Motor Manufacturing Alabama and equipped with either a 2.0 liter or 2.4 liter Gasoline Direct injection engine. In the affected vehicles, metallic debris may not have been fully removed during manufacturing of the engine crankshaft. If the debris was not completely removed, oil flow may be restricted through the connecting rod bearings, causing connecting rod damage. A worn connecting rod bearing will produce a metallic, cyclic knocking noise from the engine and possible engine failure.
Fix. Hyundai will notify owners, and dealers will inspect the vehicles and replace the engine assembly, as necessary, free of charge. Additionally, Hyundai Motor America will increase the warranty for the engine sub-assembly (short block) to 10 years/120,000 miles for both original and subsequent owners of 2011 and 2012 Sonatas manufactured at Hyundai Motor Manufacturing Alabama equipped with 2.0 lite
13V356000 Aug 2013 Power Train Sorento 2014
Kia Motors Corp. is recalling certain model year 2014 front wheel drive Sorento vehicles manufactured January 7, 2013, through March 12, 2013; and equipped with 2.4 liter engines. Due to a manufacturing issue, the right front axle shaft may fracture.
Fix. Kia will notify owners, and dealers will replace the front axle shaft assembly, free of charge. The recall began on September 9, 2013. Owners may contact Kia at 1-800-333-4542 . Kia's recall number is SC099.
13V355000 Aug 2013 Power Train Santa Fe 2013
Hyundai is recalling certain model year 2013 front wheel drive Santa Fe Sport vehicles manufactured July 13, 2012, through March 12, 2013; and equipped with 2.4 liter engines. Due to a manufacturing issue, the right front axle shaft may fracture.
Fix. Hyundai will notify owners, and dealers will replace the front axle shaft assembly, free of charge. The recall began on September 19, 2013. Owners may contact Hyundai Custom Care Center at 1-800-633-5151. Hyundai's recall number is 112.
Show all 8
11V261000 Apr 2011 Power Train Santa Fe 2010
Hyundai is recalling certain model year 2010 santa fe 2wd vehicles equipped with automatic transmissions and 2.4l engines manufactured from october 15, 2009 through march 5, 2010. The intermediate shaft may suffer from noise and excessive wear due to a misalignment of the intermediate shaft with the right side output gear. Continuing to drive the vehicle in this condition leads to the development of a whirring/whining noise and can eventually cause damage to the automatic transmission.
Fix. Dealers will replace the right side output gear and intermediate shaft free of charge. The safety recall is expected to begin during june 2011. Owners may contact hyundai's customer assistance center at 1-800-633-5151.
11V258000 Apr 2011 Power Train Sorento 2011
Kia is recalling certain model year 2011 sorento 2wd vehicles equipped with automatic transmissions and 2.4l engines manufactured from the start of production through may 22, 2010. The intermediate shaft may suffer from noise and excessive wear due to a misalignment of the intermediate shaft with the right side output gear. Continuing to drive the vehicle in this condition leads to the development of a whirring/whining noise and can eventually cause damage to the automatic transmission.
Fix. Dealers will replace the right side output gear and intermediate shaft free of charge. The safety recall is expected to begin during may 2011. Owners may contact kia at 1-800-333-4542.
NHTSA recalls on these cars and model years whose text names this engine (its size or name). The rest (brakes, air bags, wiring ...) are on each car year's page.
In owners' words
There was an update that shouldve been completed on my car that was not. There were 7 recalls on my car that I was never informed of and now they will not fix it. The engine rod went bad due to this and there is a class action settlement going on about it
2019 owner · NHTSA complaint 11777238
Vehicle: 2013 Hyundai Sonata GLS Recall: 22V-312 / Hyundai 227 Incident: Engine-compartment fire Date: November 8, 2026 Description: Smoke appeared while driving. I pulled over and turned the vehicle off, then it caught fire.
2013 owner · NHTSA complaint 11776709
My engine is making a knock sound coming from the bottom end of motor I was driving it and no warning or anything it just started knocking
2016 owner · NHTSA complaint 11775539
Against the other everyday engines
| Engine | Years | Complaints | Name the engine | Stalled or lost power | Burning oil | Recalls naming it |
|---|---|---|---|---|---|---|
| 1.5 EcoBoost | 2014–25 | 5,622 | 66% | 15% | 0.2% | 2 |
| 6.2 V8 (Gen V) | 2014–25 | 7,219 | 65% | 24% | 2.2% | 2 |
| 2.4 Theta II | 2010–22 | 21,551 | 51% | 20% | 8.1% | 8 |
| 2.4 Ecotec | 2010–17 | 6,096 | 51% | 21% | 18% | 0 |
| 3.0 EcoDiesel | 2014–23 | 2,871 | 50% | 24% | 0.2% | 7 |
| 3.3 Lambda II | 2013–21 | 3,254 | 50% | 17% | 5.9% | 2 |
| 2.0 EcoBoost | 2012–25 | 9,735 | 48% | 12% | 0.1% | 0 |
| 2.0T Theta II | 2011–22 | 3,325 | 44% | 18% | 4.8% | 2 |
| 1.4 Turbo | 2011–22 | 3,926 | 39% | 17% | 0.9% | 2 |
| 2.4 Tigershark | 2014–22 | 9,631 | 35% | 34% | 4.5% | 5 |
| 1.5 Turbo | 2016–25 | 4,471 | 33% | 27% | 0.3% | 1 |
| EA888 2.0T | 2009–25 | 7,443 | 29% | 16% | 3.7% | 5 |
| A25A | 2018–25 | 2,979 | 26% | 12% | under 0.1% | 1 |
| 1.5 Turbo | 2017–22 | 6,390 | 26% | 14% | 0.2% | 0 |
| J35 V6 | 2003–25 | 24,038 | 24% | 14% | 0.9% | 4 |
| Skyactiv-G 2.5 | 2014–25 | 2,631 | 22% | 11% | 2.7% | 1 |
| 2.7 Turbo | 2019–25 | 1,090 | 22% | 12% | 0.5% | 0 |
| 2AZ-FE | 2001–09 | 7,176 | 22% | 3.7% | 8.6% | 0 |
| 5.4 Triton | 2005–14 | 3,952 | 21% | 15% | 0.1% | 3 |
| 5.7 HEMI | 2003–24 | 23,895 | 19% | 23% | 0.1% | 6 |
| QR25DE | 2002–20 | 16,161 | 19% | 14% | 1.5% | 4 |
| 5.3 V8 (Gen V) | 2014–25 | 13,191 | 18% | 13% | 0.5% | 3 |
| 3.6 Pentastar | 2011–25 | 34,634 | 18% | 16% | 0.4% | 9 |
| 2.3 EcoBoost | 2015–25 | 3,975 | 16% | 9.9% | 0.1% | 12 |
| 3.8 Lambda II | 2020–25 | 4,423 | 16% | 8.0% | 5.6% | 0 |
| FB20 | 2012–25 | 2,336 | 15% | 8.2% | 1.7% | 0 |
| 3.6 V6 | 2009–23 | 14,214 | 14% | 14% | 0.1% | 1 |
| K24 | 2002–19 | 15,062 | 14% | 5.1% | 1.6% | 0 |
| 2GR-FKS | 2016–24 | 3,758 | 12% | 11% | 0.2% | 2 |
| 3.5 Cyclone V6 | 2007–19 | 21,313 | 12% | 11% | 0.1% | 0 |
| VQ35 V6 | 2002–25 | 12,613 | 12% | 11% | 0.2% | 1 |
| 3UR-FE | 2007–21 | 1,377 | 12% | 8.8% | 0.4% | 0 |
| FB25 | 2011–25 | 9,853 | 11% | 6.2% | 1.5% | 0 |
| 2AR-FE | 2009–18 | 4,673 | 11% | 6.6% | 1.3% | 1 |
| 2GR-FE | 2005–18 | 8,680 | 10% | 3.5% | 0.3% | 0 |
| 3.8 V6 | 2007–11 | 7,877 | 9% | 17% | 0.5% | 0 |
| 5.3 V8 (Gen IV) | 2007–14 | 9,241 | 8% | 4.5% | 1.3% | 0 |
| 1GR-FE | 2003–24 | 5,757 | 7% | 4.0% | under 0.1% | 0 |
| 4.8 V8 | 2007–13 | 726 | 6% | 4.8% | 0.1% | 0 |
Shares of each engine's own complaints, matched by VIN. They show what owners complain about, not how often engines break.
Quick answers
Is the Hyundai / Kia 2.4 Theta II reliable?
No one reports sales by engine, so there's no per-car score. Of the 21,551 complaints owners filed about cars with it, 51% name the engine, #3 of the 39 everyday engines we track (1 = the most). 4,565 (21%) say the engine knocked, seized or failed, against 2.7% for the other engines. 1,070 (5.0%) were filed with a fire reported, against 1.2% for the other engines.
What cars have the Hyundai / Kia 2.4 Theta II?
In our data: the Hyundai Sonata, Kia Optima, Kia Sorento, Hyundai Santa Fe, Kia Sportage and Hyundai Tucson, model years 2010–2022, matched by the VIN in each owner complaint.
What are the most common 2.4 Theta II problems?
In owner complaints to the government: engine, electrical, steering.
How many recalls name the 2.4 Theta II?
8 NHTSA recalls on these cars name it.
Complaints: NHTSA owner complaints filed under each car's own NHTSA names (the same ones its car pages count), all years filed, one per complaint number. Engine: decoded from the complaint's VIN with NHTSA's vPIC decoder (displacement, cylinders, engine model, turbo, hybrid) and the engine maker's model years; a VIN that doesn't decode to exactly one engine is left out. Older cars have had more years to collect complaints, and popular cars draw more because more were sold. Source: NHTSA owner complaints (FLAT_CMPL + COMPLAINTS_RECEIVED_2025-2026), received through 20261111; engines: NHTSA vPIC VIN decoder (batch); NHTSA recalls API. Engine names and model years: Hyundai.