2018 Hyundai Sonata: excessive oil consumption

Filed Sep 21, 2026 · Engine · IL

Hyundai dealership confirms I am in need of a new engine due to large oil consumption which is a known issue on 2018 Hyundai Sonata engines. Hyundai will not approve repairs because I am the second owner and vehicle is out of the 5 year warranty period. I only have 52K miles on my vehicle.

Filed Jul 20, 2026 · Engine · TX

The lower aluminum engine oil pan developed a structural hairline fracture ("micro-crack") directly along the factory casting ridge adjacent to the drain plug. The component failed without any external impact, road hazard, scraping, or underbody damage. The failure was officially confirmed and documented by Eckert Hyundai during a service visit on July 13, 2026 (Case #42971835). Following the dealer oil service, the fracture degraded into an active, worsening oil drip that requires a catch tray under the vehicle to capture leaking fluid. The vehicle is currently available for inspection. Safety Risk: An active engine oil leak poses a significant safety hazard. Rapid or continuous loss of engine oil can cause sudden oil starvation, severe engine seizure, or total power loss without warning while driving at highway speeds, increasing the risk of a crash. Furthermore, dripping oil contacting hot exhaust or engine components presents a potential fire hazard. Prior Symptoms / History: This vehicle has a well-documented history of severe internal engine issues and thermal stress, including excessive oil consumption (running 1.2 quarts low in 1,127 miles), valve cover gasket failure, and severe drivetrain vibrations from failing front axles. The excessive internal crankcase pressure and thermal stress from these underlying defects contributed directly to the material fatigue and structural failure of this aluminum oil pan.

Filed Jun 19, 2026 · Engine · NJ · fire

Vehicle caught fire after repeatedly taking it to Hyundai for service . I complained about the oil consumption and knocking noises while the vehicle was still under warranty and it was denied.

Filed Jun 16, 2026 · Engine, Transmission · OH

Check engine light solid/engine failure while driving. 2018 Sonata SE purchased new in fall 2018. Around 50,000 miles started noticing oil level drop and had to add more before next scheduled change. Dealership service center said I just had to shorten the mileage between changes which didn't seem appropriate for a vehicle with 50,000 miles but I did. Continued to have oil consumption problem with no signs of leak, no burning oil smell or exhaust issues. Dashboard display would go off and when I immediately checked dipstick there was barely any oil so I'd add more then go in for full change. At 67,000 or so miles in June 2026, without oil display going off the engine light was now solid. Got to reputable service center near my home and oil was under a quart left yet the warning lamp hadn't gone off. They ran the engine error code P0304 and was misfire #4 cylinder and after compression test, #3 was very low and #4 very high. NOT drivable at that point then towed to dealership so yes, available for inspection by the federal safety agency at the dealership. For now they claim a 'tune up' is needed for spark plug replacement, valve cover gasket replace and fuel induction service that's my cost to incur which seems to just be fixing the damage of an engine oil consumption problem not fixing the issue that caused the damage. The engine seized/stalled without warning while I was driving the vehicle (granted at low speed in my neighborhood when the engine light turned on). I would not say the engine warning lamp occurred prior to the engine fail, it happed at the same time. This should not happen for a vehicle with my mileage and regular maintenance. I looked up the federal safety agency for potential recall or other helpful information and started to see extremely similar scenarios to mine and wanted to add complaint as well. This is getting very expensive outside of whatever cost the dealer wants as a fix with rental car needed and tow services. Thank you for your consideration of this engine safety issue.

Filed Jun 13, 2026 · TX

I was only in the car for about 4 minutes then came to a stop light. Once the light had turned green I pressured down on the gas, my car rolled for a second then died on me, causing it to go into accessory mode. Instantly three lights came on: the check engine light, battery light, and low oil light. The car would take at least 5 seconds to turn back on then would fall back into accessory mode randomly. Tried to jump the car 4 times, issue still remains. What sucks about this is that the mechanic shop can’t even figure out what’s wrong. They thought it was the high pressure fuel pump..turns out it’s not.

Filed May 12, 2026 · Engine, Fuel system · CA

Engine blown out malfunction took two dealer Hyundai Folsom Lake stated rings are bad sludge buildup in engine and stayed at Hyundai motor America denied engine replacement due to knowledge under Theta two engine extended warranty settlement of 150,000 MI 15 years I'm still within warranty but are still being denied had numerous of issues with vehicle oil consumption knock knock sensor replace and other maintenance done since purchase vehicle brand new in 2018

Filed May 6, 2026 · Engine, Fuel system · TX

I am submitting this complaint to report a serious and ongoing safety defect involving the engine of my 2018 Hyundai Sonata Sport equipped with the 2.4L Theta II engine. The vehicle has been officially tested and documented by Hyundai as consuming more than two (2) quarts of engine oil per 1,000 miles, which Hyundai has acknowledged following completion of its oil consumption test procedure. Despite this confirmation, Hyundai has declined to fully correct the defect. As the condition has progressed, the engine now fouls spark plugs every 350–500 miles, resulting in: •Engine misfires •Loss of power during operation •Rough running and hesitation •Risk of sudden engine stalls while driving This condition occurs without warning and requires repeated roadside or emergency repairs simply to keep the vehicle operable. The condition has deteriorated further, requiring replacement of fouled spark plugs every 350-500 miles. Loss of power and engine shaking can occur at any time, presenting a safety hazard for me and other drivers.

Filed May 5, 2026 · Engine · AR

Despite proper maintenance, the vehicle is burning oil at an excessive rate. I have already replaced the oil pan, but the issue persists. I now have to add oil frequently between oil changes. This creates a serious safety concern, as low oil levels can cause engine failure while driving, leading to sudden loss of power or stalling in traffic. This puts me, my passengers, and other drivers at risk. There are no visible leaks, which suggests the oil is being burned internally. This appears to be a potential defect rather than normal wear and tear. I am requesting that this issue be investigated as it may affect other vehicles of the same make and model. This is becoming very expensive having to refill oil as the dipstick shows nothing. This has been confirmed by technicians that there has been no oil in my car despite coming in on time or before the recommended miles. The oil light will come on a few weeks after having the oil changed. It seems this is an issue with this engine type.

Filed Apr 2, 2026 · Engine, Fuel system · UT

Had an oil change, then 2 weeks later car making noise, checked the oil and it was completely empty, so we refilled the oil. Then a month after again same issue no oil, refilled it again and now a week later it's 2 quarts low already. Also when I come to a complete stop when it is time to go again it's very slow at going or if I try to excel it takes it a very long time to actually excel I think something's wrong with the fuel pump

Filed Mar 15, 2026 · Engine · CA

2018 Hyundai Sonata 2.4L Theta II engine experiencing severe oil consumption and loss of oil pressure. Oil pressure warning light actively blinking and dipstick completely dry. This is consistent with the known Theta II engine defect subject to prior the federal safety agency investigations and class action settlements. Mission Hills Hyundai documented low oil concern in service notes during December 2025 visit but failed to take any action and returned the vehicle without repair. Hyundai Consumer Affairs has been unresponsive and provided conflicting information regarding recall completion on this vehicle. This is a serious safety defect that puts the driver at risk of engine failure while operating the vehicle.

Filed Mar 9, 2026 · Engine · TN

Excessive Oil Burning and Oil Consumption. Oil turns black abnormally quickly (within the first 500-1000 miles) even though recommended Full-Synthetic Oil is used. Engine has intermittent rough idle once engine is warm. Occasionally engine experiences "near-stall" and "misfire event", causing the battery light to flash on dashboard. >>>Oil consumption rate is approximately 3-4 quarts per 1,000 miles<<< ***Maintenance completed since purchase*** Coolant Flush - Replaced PCV Valve (NEW) - Replaced Valve cover Gasket + Oil Pan / Oil Pan Gasket (recommended by dealer) (NEW) - Replaced Spark Plugs (recommended by dealer) (NEW) - Replaced Battery (NEW) - Replaced Alternator (NEW) - Replaced both engine accessory belts (NEW) - Replaced 150A main fuse (located on positive battery terminal) (NEW) - Used Hyundai brand oil filters - Used Chevron/Techron Complete Fuel system cleaner twice, between and at oil change (as recommended by "Twin City Hyundai" dealer in Alcoa, TN) ***Had dealership inspect it for approval of known Federal Recall on GDI Engines for excessive oil consumption / engine seizing issues; dealership claimed it did not pass re-call approval*** SYMPTOMS STILL PERSIST Mileage is now approx. 80K

Filed Feb 20, 2026 · Engine · CA

The component involved is the engine (2.4L Theta II gasoline engine) in my 2018 Hyundai Sonata. The malfunction involves excessive internal engine oil consumption between oil changes. The vehicle consumes oil at an abnormal rate, requiring frequent top-offs to prevent low oil levels. The vehicle is available for inspection upon request. This condition creates a safety risk because excessive oil consumption can lead to critically low oil levels, engine seizure, sudden engine stall, or loss of propulsion while driving. A sudden engine stall or loss of power while operating at highway speeds could increase the risk of a crash. The problem has been inspected and documented by an authorized Hyundai dealership. During service, the dealership recorded that the customer reported oil burning between oil changes and noted evidence of engine oil consumption. No permanent repair has been performed. The issue remains unresolved. Hyundai Motor America has not physically inspected the vehicle directly but has reviewed the case through customer care. The manufacturer has required additional diagnostic testing at the owner’s expense as a condition of further evaluation and declined to authorize testing at no cost or provide assurance of reimbursement. No crash, fire, or injury has occurred to date. The vehicle has not been inspected by police or insurance representatives. There were no warning lamps illuminated at the time the oil consumption was first observed. The condition was first noticed when oil levels were found to be significantly low between scheduled oil changes. The issue has been ongoing and progressive. Given the known history of engine-related issues involving Hyundai Theta II engines, I am submitting this complaint due to concerns that continued oil consumption may result in engine failure, sudden stall, or loss of propulsion while driving, creating a potential safety hazard. The vehicle remains in service but the condition has not been corrected.