The Hyundai 2.4L inline-4 engine made its debut in the 2007 Sonata with the Theta II MPI designation. Within several years came the 2.4 Theta II GDI engine utilizing gasoline direct injection (GDI). Despite it’s larger displacement the smaller 2.0T Theta II engine actually makes more power. This is due to the fact the 2.0 offers turbo options while the 2.4L is NA. Nonetheless, the Hyundai 2.4 engine offers a good all around balance. No engine is perfect, though. In this article, we discuss Hyundai 2.4 Theta engine specs, problems, reliability, and more.
What Cars Use the 2.4L Theta II?
We’ll split this topic into two sub sections since there are two primary Theta II engines. It’s important to layout some of the changes between 2.4L MPI and GDI engines. Below we’ll dive into the years and models with each engine along with some changes and updates.
Hyundai 2.4 MPI Engines
Original 2.4 Theta II engines are built off the original 2.4L Theta engine. Our main focus in this article is the Theta II since it’s the most popular engine by a large margin. However, a lot of the topics do apply to the original engine. Anyways, the 2.4 MPI is in the following Hyundai/Kia years and models:
- 2007-2019 Hyundai Sonata
- 2010-2020 Hyundai Tucson
- 2010-2020 Hyundai Santa Fe
- 2008-2012 Kia Forte
- 2008-2019 Kia Optima
- 2011-2021 Kia Sportage
- 2009-2020 Kia Sorento
This variant of the 2.4L inline-4 engine has a 10.3:1 compression ratio and offers 177hp and 170 lb-ft of torque. The performance is nothing to write home about, but it’s enough for many.
2.4L GDI Engine
Shortly after the MPI came the 2.4 GDI Theta II engine. It’s in the following Hyundai and Kia models:
- 2012-2020 Hyundai Santa Fe
- 2009-2019 Hyundai Sonata
- 2015-2020 Hyundai Tucson (TL)
- 2011-2019 Kia Cadenza
- 2010-2019 Kia Optima
- 2010-2021 Kia Sportage
- 2014-2020 Kia Sorento (UM)
An increase to 11.3:1 compression ratio is one notable change. The increase for Hyundai 2.4L engines is mostly enabled by the intro of direct injection – known as GDI. Power comes up to 200hp and 184 lb-ft (later years actually offer a bit less).
Anyways, the update to direct injection offers many benefits for performance and fuel economy. There is one flaw with direct injection, though. Carbon build-up is a topic we’ll cover as a 2.4 Theta II common engine problem. It’s a small trade-off for what is otherwise a great update.
Hyundai 2.4 Specs
Specs for the Hyundai 2.4 inline-4 engine are as follows:
|Engine||Hyundai 2.4 Theta|
|Displacement||2,359cc (144 cu in)|
|Valvetrain||DOHC, 16 valve|
|Compression Ratio||10.3 : 1 thru 11.3 : 1|
|Bore x Stroke||88mm x 97mm|
|Torque (lb-ft)||161-184 lb-ft|
Original 2.4 Theta engines came out in 2004 with 163 horsepower and 161-166 lb-ft of torque. It also uses a 10.5:1 compression ratio. Again, this engine is not our primary focus but a lot of the info applies. Our main focus is the Hyundai 2.4 Theta II MPI and GDI engines. They all share the same exact 2.4L inline-4 design with DOHC, aluminum blocks and heads, and an 88mm bore x 97mm stroke.
Theta II 2.4 GDI engines see a solid boost in power thanks to the efficiency of direct injection, which allows an 11.3:1 compression. Anyways, these engines aren’t anything special on paper in terms of specs or power output. The Hyundai 2.4 inline-4 is far from a performance engine, but it gets the job done for most.
Hyundai 2.4 Theta Engine Problems
A few of the most common problems with the Hyundai 2.4 engine include:
- Engine failure
- High Oil Consumption
- Carbon deposits
- Oil leaks
These topics will be a major focus throughout the rest of this article. However, before jumping in it’s important to add a few quick notes. We’re considering these among the most common Hyundai 2.4 Theta engine problems. It doesn’t mean the failures are actually common in the true sense of the definition. Rather, when issues arise these are some common areas.
Unfortunately, the 2.4L Theta II engine doesn’t have the best rep when it comes to reliability. A good warranty and some recalls along the way do make some reliability flaws less concerning. Anyways, we’ll circle back to 2.4 MPI and GDI reliability at the end of the article. For now, let’s discuss the above Hyundai Theta engine problems.
1) 2.4L Theta II MPI & GDI Engine Failures
Engine failure is a topic we wrote about for the 2.0T Theta engine as well. The 2.4L engine actually shares many of the same issues, and sadly engine failure is one of them. This issue can affect all years and models. However, engine failure is most common among 2011-2014 Hyundai Sonata and 2013-2014 Santa Fe. Problems also affect the 2.4 Theta II engines in some Kia models of similar years. This includes the Optima, Sorento, and Sportage.
We won’t beat this topic to death since it’s been covered quite a bit. Kia and Hyundai had to pay some pretty hefty fines regarding these problems due to safety concerns of engine failures. There were recalls issued and many engines were replaced either as a part of the recall or during warranty.
The root cause of engine failures lies within the rod bearings. Debris during manufacturing wasn’t properly removed and it eats up the 2.4L Theta II rod bearings due to poor oil flow. They ultimately seize and cause complete engine failure. We think this is mostly a non-issue for the Hyundai 2.4 engine as of 2021. It’s still something to keep in mind since engine failures can be very costly repairs.
Hyundai/Kia Theta Engine Failure Symptoms
Symptoms of serious engine problems or failures on the 2.4 Theta II engines include:
- High oil consumption
- Engine knocks
- Poor overall performance
- No start / stalling
Engine failure symptoms on the Hyundai Theta engine can be broad. It all depends on the severity of the issues. You’ll likely notice high oil consumption (a topic we’re covering more in-depth next). This can lead to white smoke from the exhaust. Otherwise, the 2.4L inline-4 engine may product knocking sounds as the bearings develop problems.
You might also notice poor overall engine performance. When failures are severe the engine can seize which will cause stalling and no start situations. At this point you’re at the point of complete engine failure.
2.4L Theta II Engine Failure Fixes
As bearings wear they chew up the crankshaft and can lead to rod knock, piston slap, and more problems. It doesn’t make sense to rebuild an engine with this degree of damage. As such, the Hyundai/Kia will need a new 2.4 Theta engine. Many failures were already covered under warranty or recalls. Hopefully this isn’t a major flaw as of 2021, especially for models with replacement engines.
Still, if you end up paying out of pocket this can easily be a $5,000+ replacement. Given the recalls and fines it’s clear Hyundai is very aware of these problems. They may still work with owners to help with repair bills or cover the failure completely. It’s worth a shot if you run into this costly problem.
2) Hyundai 2.4 Oil Consumption Problems
Excess oil consumption sometimes relates to the previous topic. However, we’re ignoring high oil consumption due to actual engine problems or failures. There are plenty of cases of Hyundai 2.4 Theta engines burning a lot of oil without any other obvious problems. The 2.4L inline-4 engine isn’t along in these issues, though.
Engine naturally consume some oil. This is true of any internal combustion gasoline engine. Some oil is often lost due to blow-by past the piston rings. Metals expand with heat, so piston rings gaps are wider on cold engines. This means most excess oil consumption problems on the Hyundai 2.4L engine are when the engine is cold.
Anyways, usually high oil consumption isn’t a major problem in the shorter-term. It’s a bit more concerning on the 2.4 Theta II engine, though. The engine has some proven internal flaws, so excess oil consumption could be a sign of deeper problems. If you’re losing ~1 quart of oil every 1,000 miles or less then it’s time to find the root cause.
Theta GDI/MPI Oil Consumption Symptoms
Look for the following symptoms that may point to excess oil consumption and/or sign of larger problems:
- Losing 1+ quart every 1,000 miles
- Burning oil scents
- Knocking or pinging sounds
- White smoke from exhaust
Oil consumption is typically considered excessive when the 2.4L Theta is burning more than 1 quart every 1,000 miles. You may notice burning oil smells or smoke from the exhaust. This indicates excess oil is burning off in the cylinders, and can point to deeper internal problems. Knocking or pinging sounds can also indicate a serious problem.
However, if excess oil consumption is your only symptom then you may be OK. As engines age a bit more oil consumption may be normal.
3) 2.4 Theta GDI Carbon Build-Up Issues
Carbon build-up does not apply to the 2.4 Theta MPI engines. Those engines utilize multi-point injection (MPI), which is also known as port injection. The engine sprays fuel into the intake ports where it mixes with air and travels into the cylinders. On the other hand, Hyundai 2.4 GDI engines spray fuel directly into the cylinders.
We talked about oil blow-by a little bit with the oil consumption. All engines produce some oil blow-by. Some of that makes its way into the intake where it can stick to intake ports and valves. With port injection the fuel is able to wipe away any oil. However, direct injection does not have that benefit. Therefore, oil sticks to the valves and forms carbon deposits.
Over time, the Hyundai 2.4L GDI inline-4 engine gets carbon build-up on the intake ports and valves. It can restrict air-flow into cylinders and cause performance and drivability issues. It’s not always easy to detect since it occurs over a period of 5+ years and 80,000+ miles. Carbon build-up doesn’t present major threats to engine reliability or longevity.
Many 2.4L GDI engines will probably make it their whole lives without intake valve cleaning. It’s a good idea to address carbon build-up every 100,000 miles, though. More on that when we discuss Hyundai 2.4 GDI walnut blasting below.
2.4L Inline-4 GDI Carbon Build-Up Symptoms
A few symptoms of carbon build-up problems on the Hyundai & Kia 2.4 Theta GDI include:
- Rough / stumbling idle
- Stuttering or hesitation while accelerating
- Loss of power
Again, carbon build-up begins to restrict air-flow into cylinders. Different cylinders can also experience different degrees of carbon build-up. This can cause the Hyundai 2.4L GDI engine to misfire. You may notice a rough idle or stuttering while accelerating. These symptoms usually start slowly and become progressively worse as more build-up occurs.
Some also notice power loss and it’s a very common symptom of carbon build-up. However, it can be the hardest symptom to notice. That’s because carbon deposits form over years and years and tens of thousands of miles. The 2.4 Theta GDI power loss is a slow, gradual process and not something that happens overnight.
Hyundai 2.4 Theta GDI Walnut Blasting
Walnut blasting is a proven way to effectively clean intake valves and ports. It requires a heavy-duty shop vac and walnut media shells. The walnut shells are blasted into the intake ports with the shop-vac to remove any carbon build-up. Walnut media shells are inexpensive for the job, but labor can add a lot of costs.
The intake manifold must come off to access the Hyundai 2.4 GDI ports and valves. It’s a several hour process from start to finish, so labor can be about $300-600. Walnut blasting isn’t totally necessary, but we consider it good maintenance every ~100,000 miles.
4) Hyundai 2.4 Inline-4 Oil Leaks
Oil leaks on the 2.4L inline-4 MPI and GDI engines is a pretty general topic. We’ll move thru this a bit faster since we’re not focusing on any one specific oil leak. Anyways, all internal combustion engines are prone to oil leaks as they age. Gaskets, seals, o-rings, and similar parts with rubber-like materials simply degrade with time and mileage.
Eventually these parts begin developing small cracks and oil leaks develop. If left alone, the cracks continue to expand or new ones form and leaks gradually become worse. A few common oil leak areas on the Hyundai 2.4 engine include the valve cover gasket, oil pan gasket, and main seals.
We don’t necessarily consider this a true common engine problem on the 2.4L Hyundai Theta II engines. There aren’t any major design flaws that cause the leaks. It’s just an important topic to cover since some 2.4 GDI and MPI engines are 10-15+ years old. Running into an oil leak or two with that kind of age and 100,000+ miles isn’t uncommon.
2.4 Theta II Oil Leak Symptoms
Oil leak symptoms are usually pretty straight-forward. Regardless, the following symptoms may point to an oil leak from the 2.4 Theta MPI and GDI engines:
- Visible leak
- Loss of oil
- Burning oil smell
- Light smoke from engine bay
Of course, if you’re seeing visible oil spots on the ground after parking the car then you probably have an oil leak somewhere. Oil loss is a possible symptom, but engines consume some oil naturally. Low engine oil alone likely doesn’t indicate a leak. Additionally, if the leak is large enough to cause large oil loss then you probably already noticed other symptoms.
Some oil leaks towards the top of the engine – like the valve cover gasket – may drip onto hot engine parts and burn off. This may cause the Hyundai 2.4 Theta engines to make burning oil smells or light smoke from the engine bay.
Hyundai 2.4 Theta Oil Leak Fix
The good news about most oil leaks is that they’re usually inexpensive gaskets or seals. These parts often only run about $10-40 for OEM replacements. If you can DIY the work then most 2.4 GDI & MPI oil leaks are very cheap repairs.
However, if you’re going to a repair shop for work then some oil leaks can add about $200-500+ in labor. It all depends on where and what is leaking, but some things are harder to access. That can lead to several hour repair times that can add a lot of money in repair bills.
2.4L Theta II Reliability
Is the Hyundai 2.4 Theta II MPI and GDI engine reliable? We think this engine earns average remarks for reliability. Severe engine problems and failures hold the reliability down. However, many 2.4L engine failures were covered by Hyundai and Kia through recalls or under normal warranty. The issues don’t seem as common with the new replacement engines, so hopefully that’s a long-term solution.
Carbon build-up is a flaw on the Hyundai 2.4 Theta II GDI engine. However, direct injection is great technology so it’s a small downside to an otherwise great update. High oil consumption and oil leaks are a few other common problems on the Hyundai 2.4 Theta engines.
A lot of reliability simply comes down to maintenance and luck of the draw. We can’t control the luck factor. However, you can control how well you maintain the Hyundai/Kia 2.4L inline-4 engine. Use quality oils, change fluids on time, and fix problems if and when they occur. Do all of this and the Hyundai 2.4 Theta engine can offer solid reliability with just a little luck on your side.
What’s your experience with the 2.4 Theta MPI/GDI engine? Are you considering one?
Leave a comment and let us know!