The Hyundai 2.4 engine is a temperamental one that has had its fair share of issues over the years. One of the most commonly reported problems with the 2.4L GDI Theta II engine is excessive oil consumption.
There is quite a bit of speculation as to the root cause of excessive Hyundai 2.4 oil consumption, but most Hyundai mechanics agree that it is caused by the engine’s direct injection system which causes carbon buildup to accumulate in the piston oil control rings. This prevents the rings from being able to clear enough oil from the engine’s cylinder walls, allowing it to burn off in the combustion chamber.
This issue affects both Hyundai and Kia vehicles that use the 2.4 Theta II GDI. However, excessive oil consumption is common in the majority of Hyundai’s direct-injected engines. The most troublesome engines include the Hyundai 2.0L GDI, and 1.6L Gamma GDI. In fact, the issue became so apparent that the NHTSA had to step in and investigate the oil consumption issue, along with a host of other issues with the Theta II.
While we have already written an article about the 4 Most Common Hyundai 2.4 Engine Problems, this guide will discuss the Hyundai 2.4 oil consumption issue in more detail.
2.4 Theta II GDI Applications and Affected Models
The following vehicles have all been named in a class action lawsuit involving excessive 2.4 Theta II oil consumption issues:
- Hyundai Grandeur/Azera (2011–2019)
- Hyundai Santa Fe (2012–2020)
- Hyundai Sonata (2009–2019)
- Hyundai Tucson (TL) (2015–2020)
- Kia Cadenza (2011–2019)
- Kia KX7 (2016–2021)
- Kia Optima (2010–2019)
- Kia Sportage (2010–2021)
- Kia Sorento (UM) (2014–2020)
The following vehicles were also listed in the Hyundai oil consumption lawsuit, but use a different Hyundai direct-injected engine including the 2.0L Theta II GDI, Kappa GDI, and Nu GDI engines.
- 2012-2020 Hyundai Elantra
- 2009-2018 Hyundai Genesis Coupe
- 2019-2021 Hyundai Kona
- 2020-2021 Hyundai Palisade
- 2011-2021 Hyundai Veloster
- 2020-2021 Hyundai Venue
- 2010-2021 Kia Forte
- 2017-2020 Kia Niro
- 2012-2021 Kia Rio
- 2011-2020 Kia Sorento
- 2012-2021 Kia Soul
- 2018-2021 Kia Stinger
- 2022 Kia K5.
2.4 Theta II GDI Oil Consumption Symptoms
The most common symptom of excessive 2.4 Theta GDI oil consumption is an illuminated engine oil level or oil pressure light caused by low engine oil. In many cases, owners of affected vehicles aren’t aware that their engine is burning an excessive amount of oil until their low engine oil light comes on. At this point, it is possible that engine damage has already occurred due to a lack of lubrication.
The tricky aspect of this problem is that there aren’t a ton of warning signs that excessive oil consumption is occurring until it is too late. However, some other common warning signs of low engine oil. These include a pronounced oil burning smell inside the cabin, engine overheating, poor performance, or an audible knocking sound coming from under the hood.
Unfortunately, low engine oil can exacerbate other common problems with the 2.4 Theta engine. To read more, take a look at our Common Hyundai 2.4 Engine Problems Guide. For that reason, it is extremely important to check your oil frequently if you own one of the affected Hyundai or Kia vehicles.
Hyundai 2.4 Excessive Oil Consumption Cause
The primary cause of excessive oil consumption in the Hyundai 2.4 Theta engine is the design of the engine’s gasoline direct injection system. It allows for excessive carbon buildup on the intake valves to fall and collect in the engine’s piston rings.
The 2.4’s direct injection system sprays fuel directly into the cylinder at high pressure. This is in contrast to a more traditional port injection fuel system which injects fuel into the intake ports. While direct injection systems are unquestionably more efficient and perform better overall, the one consequence is carbon buildup on the intake valves. With a port injection system, the fuel sprayed on the intake valves cleans the valves. Since direct injection systems, like the one found on the Hyundai 2.4 Theta II GDI, bypass the valves, excess carbon from the combustion process builds up on the valves.
On the 2.4 Theta, this carbon buildup can then flake off and fall into the piston area. The particles can get trapped in the piston rings which makes them very inefficient at clearing oil from the cylinder walls. The excess oil on the cylinder walls then goes into the combustion chamber, burning off with the air and fuel.
This problem has led to some extreme cases of Hyundai/Kia owners having to add 3 quarts of oil every 1,000 miles or more. Hyundai and Kia consider any more than 1 quart every 1,000 miles to be excessive in their literature.
Bad Hyundai 2.4 PCV Valve
Replacement Hyundai/Kia PCV Valve: Amazon.com
Outside of the design of the 2.4 Theta’s direct injection system, a clogged or failing PCV valve is another frequently cited cause of excessive oil consumption. As with any engine, the constant movement of the pistons generates pressure in the crankcase. The job of the PCV system and PCV valve is to alleviate that pressure. It does that by recirculating blowby gas back into the engine. The PCV valve is a crucial component in the system. Its main job is to control how much vacuum is applied to the crankcase.
If the PCV valve gets clogged or damaged, excess pressure can build up in the crankcase. This can cause oil leaks from all of the main gaskets. This is obviously an issue, as your engine will lose a significant amount of oil that way. If your 2.4 Theta’s PCV valve gets stuck open, the valve allows oil to get sucked through the PCV system. It is then routed into the intake manifold where it will then enter the combustion chambers and burn off.
Regardless of which way your Hyundai/Kia’s PCV valve breaks, it can lead to extreme oil consumption/oil loss issues. Luckily, the Hyundai 2.4 PCV valve is inexpensive and easy to replace. It is a good option if you want to try to fix your oil consumption first without jumping to extreme conclusions about the cause. Replacing the 2.4 Theta’s PCV valve has had varying levels of success for owners. Some claim that it fixed the problem entirely while others claim that it was only a temporary fix.
Excessive Hyundai 2.4 Oil Consumption Fixes
Due to the nature of the 2.4L Theta II’s oil consumption issues, there is little that you can actually do to repair the issue it has begun. This has to do with the fact that the problem stems from the engine’s design itself. It isn’t caused by a single problem part or component. With that being said, there are some steps that you can take to limit the risk of complete engine failure from excessive oil consumption.
Frequent Oil Checks and Lower Oil Change Intervals
While the first part of this section won’t prevent the Hyundai 2.4 oil consumption problems from happening, it will give you a bit more of a heads-up that the problem is occurring. While checking your oil frequently is good practice, many people neglect to do it. It is even more important to check your frequently with a 2.4L Theta engine due to its laundry list of problems that revolve around low engine oil.
Due to the fact that the Hyundai 2.4 can develop oil consumption issues at any point, it is a good idea to check your oil every 1,000 miles or once a month. This will ensure that worst case, your engine will still have a functional amount of oil in it before you realize that there is a problem. You may want to check your 2.4 Theta more frequently than that if you have a high-mileage engine, as these problems are more common after the 70,000-mile mark.
Some 2.4 Theta owners also recommend changing your oil more frequently than the owner’s manual recommends. The manual states that oil changes on the Theta II GDI should be done every 7,500 miles or 12 months. Nearly everyone agrees that is too long to wait. Most owners will change their oil around the 4,500-5,000 mark. This will help ensure that the oil in the engine is still providing ample lubrication to the engine’s components.
Hyundai 2.4 PCV Valve Replacement
As we mentioned above, a faulty or damaged Hyundai 2.4 PCV valve can be a potential cause of oil consumption problems. With that being said, it is not a guaranteed fix. Most people that have performed a PCV valve replacement claim that it was indeed a short-term solution. In most cases, the issue resurfaced later in the engine’s life.
While it might not be a guaranteed fix, it is still worth a try. Replacing the 2.4 Theta’s PCV valve only costs around $10 and 20 minutes of your time. The only tools required for the job include a set of pliers, a 21mm socket with a corresponding socket wrench, and a flathead screwdriver. The job mainly includes removing the engine cover, pulling off the PCV piping, unscrewing the old PCV valve, screwing the new one in, and reinstalling the hose. Here is a demonstration of the process:
Ultimately, for such a small price and minuscule time commitment, it is worth giving a 2.4 Theta PCV valve replacement a try. If this doesn’t work or the problem returns, you’ll likely need to bring your vehicle in for an inspection.
Hyundai Extended Warranty/Manufacturer Help
Hyundai 2.4 Theta Extended Warranty Information: NHTSA.gov
Due to a number of issues with the 2.4L and 2.0L Theta II GDI, Hyundai was forced to extend the warranty of multiple vehicle with the engine. A number of vehicles with the engines had their powertrain warranty extended from 10 years/100,000 miles to 10 years/120,000 miles if it met certain criteria. This extended powertrain warranty was mainly directed at 2.4L Theta owners that experienced signs of engine damage from contaminated oil.
As a result, 2.4L Theta engines that demonstrated oil consumption issues alone do not qualify for the extended warranty. That is unless the vehicle had the Knock Sensor Detection System (KSDS) software update performed at the dealer, the vehicle displayed a DTC P1326 engine code, or the vehicle showed signs of rod bearing wear. However, sometimes the oil consumption issue could lead to these problems.
When most owners of a 2.4L Theta II GDI-powered Hyundai or Kia have gone to a certified repair facility to have the issue diagnosed, they have been told that the dealer must first conduct an oil consumption test before performing a repair. This consists of the dealer filling the oil and sealing the oil cap for 1,000 miles. If the engine consumed more than 1 quart in that 1,000 miles, Hyundai would perform additional steps. Their procedure is outlined in the document below:
2.4 Excess Oil Consumption KIA TSB: NHTSA.gov
Ultimately, Hyundai has done everything that they can to sweep the issue under the rug without taking accountability for the problem. Only under very specific circumstances will they actually replace an engine under warranty.
Hyundai Oil Consumption Class Action Lawsuit
Hyundai 2.4 Oil Consumption Class Action Lawsuit information: legalscoops.com
2.4 Oil Consumption Settlement Agreement: classaction.com
Throughout the 2.4L Hyundai Theta’s build cycle, it has been the subject of a number of class-action lawsuits. A class action suit was filed citing that the 2.4 Theta II GDI, in addition to a number of other Hyundai engine series including Nu, Gamma, Lambda, and Kappa engines, are prone to excessive oil consumption due to design defects.
This is separate from the class action opened in August of 2022 involving the Theta inline-4’s tendency to accumulate contaminates in the engine’s oil, leading to prematurely worn engine parts, oil starvation, and even complete engine seizure in some cases.
The class action lawsuit is aimed at anyone who owns a Hyundai or Kia vehicle that experienced excessive oil consumption. This includes all of the 2.4L Theta-powered cars listed above. The class action claims that Hyundai has been aware of the excessive Hyundai 2.4 oil consumption problems on these engines for a while now and has refused to remedy the issue. This comes after Hyundai and Kia issued a number of technical service bulletins about the issue and repair procedure but failed to issue a recall.
While the Hyundai 2.4 oil consumption class action lawsuit began before the engine failure lawsuit, Hyundai has already settled a $210 million NHTSA agreement regarding the oil contamination lawsuit. The Hyundai oil contamination lawsuit continues, awaiting a ruling.
Hyundai 2.4 Oil Consumption FAQ
Yes, multiple Hyundai engines have excessive oil consumption issues. The Hyundai direct injection engines suffer the most. These engines include the 2.4 Theta II GDI, 2.0 Theta Turbo GDI, and other direct-injected Nu, Gamma, and Kappa engines.
5W30 fully synthetic oil is the best oil to use in the 2.4 Theta II GDI. The thicker film of 5W30 is less likely to cause rod-bearing issues down the line.
No, not all 2.4 Theta GDI engines have oil consumption issues. In fact, there are plenty of high-mileage Hyundai 2.4’s on the road that have never consumed excess oil. The problem is hit or miss, unfortunately, but it is always good to stay informed.
Hyundai 2.4L Theta GDI Oil Consumption Summary
Ever since its release, the Hyundai 2.4L Theta has been a troubled engine. From excessive internal wear to excessive oil consumption issues, the 2.4 Theta has been criticized by owners and the NHTSA alike.
The Hyundai 2.4 engine, specifically the GDI Theta II variant, has been plagued by excessive oil consumption issues. The root cause of this problem is tied to the engine’s direct injection system. Carbon buildup falls off of the intake valves and damages the piston rings. This issue is not limited to the 2.4 engine but also affects other Hyundai and Kia engines with direct injection.
Numerous Hyundai and Kia models have been affected by this oil consumption problem, leading to a class-action lawsuit. Oftentimes, 2.4 Theta owners don’t identify the problem until it is too late. While there are some potential fixes, such as replacing the PCV valve, they are not guaranteed to resolve the issue. Frequent oil checks and shorter oil change intervals are recommended to monitor oil levels. Hyundai has extended the warranty for certain vehicles with the Theta engine, but the criteria are limited, and engine replacements under warranty are rare.
Hyundai has faced legal action and settlements related to the excessive oil consumption issue, including a class-action lawsuit. The class-action lawsuit alleges that Hyundai has been aware of the problem but has failed to address it adequately.
Excessive oil consumption is an unfortunate consequence of the 2.4 Theta GDI’s design. If you have been affected by this issue, consider joining the lawsuit to potentially be compensated.