Certain Santa Fe (TMA), Santa Fe Sport (AN), Sonata (LFA), and Tucson (TL) vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. This bulletin provides instructions for updating the Engine Control Module (ECM) to address this condition.
full bulletin at NHTSA ↗2018 Hyundai Santa Fe Sport engine problems
moderate 157 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
157
Recalls
0
Avg fix
$3,100
1crash
1fire
3injuries
When does it fail?
Of the 157 engine complaints filed for the 2018 Hyundai Santa Fe Sport, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Of the 6 model years of Hyundai Santa Fe Sport we track for engine problems, this one carries the most owner complaints on file — 157.
Engine accounts for 50% of every owner complaint on file for this vehicle — the dominant problem area across 8 categories tracked.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Certain Santa Fe (TMA), Santa Fe Sport (AN), Sonata (LFA), and Tucson (TL) vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
full bulletin at NHTSA ↗Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. If present, this condition is expected to occur only within approximately the first 1-3 minutes after engine start, while the catalyst is reaching its normal operating temperature.
full bulletin at NHTSA ↗Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. If present, this condition is expected to occur only within approximately the first 1-3 minutes after engine start, while the catalyst is reaching its normal operating temperature.
full bulletin at NHTSA ↗Certain 2019 – 2020 model year Santa Fe, 2017 – 2018 model year Santa Fe Sport, 2015 – 2019 model year Sonata, and 2018 – 2021 model year Tucson vehicles may exhibit elevated engine-out emissions. Hyundai is conducting a service campaign to update the Engine Control Module (ECM) Software for vehicles equipped with the (2.4 GDI) Theta II engine to improve engine combustion and fuel trim adaptations.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2018 Santa Fe Sport engines consistently describe rapid oil loss—2 to 4 quarts per 1,000 miles—without visible leaks, accompanied by engine knock, misfires, and eventual stalling at highway speeds. The problem appears across the ownership range, from 11,600 miles (one early failure) to 150,000 miles, with no reliable warning before catastrophic failure. Multiple owners report the engine stalling while driving 50–70 mph with children aboard, forcing them onto shoulders or into ditches, and creating collision risk.
Hyundai's extended Theta II warranty (10 years/120,000 miles for rod bearing failure) is routinely denied in complaints, with the manufacturer attributing failures to secondary damage (wrist pins, pistons, cylinder scoring) or insufficient maintenance, even when owners provide complete service records. Metal shavings in the oil pan, burnt valves, and cylinder damage confirm internal failure, yet dealerships often refuse to share diagnostic data or authorize repairs. Owners report spending thousands on repeated oil consumption tests, combustion cleanings, gasket replacements, and out-of-pocket costs for engine replacement ($6,000–$12,000+). Second owners are especially vulnerable—warranty exclusions apply, and dealers routinely deny claims citing "class-action settlement complications." Hyundai's class-action settlement supposedly covers this defect, but in practice most claims are rejected or settlements are extremely slow.
Same Hyundai Santa Fe Sport engine reports on nearby years: 2015 · 2016 · 2017
Failure modes owners describe
Excessive Oil Consumption
Engine burns oil at abnormally high rates without visible external leaks. Owners report losing 2–4 quarts per 1,000 miles of driving. Secondary damage from oil starvation includes cylinder scoring, piston damage, spark plug fouling, and valve failure. Multiple owners document repeated failed oil-consumption tests conducted per dealership protocol.
When: Onset typically 40,000–90,000 miles; some owners report early failure at 11,653 miles
Symptoms owners cite: Oil level drops rapidly between scheduled changes; Check engine light illuminates; Black or discolored spark plugs requiring frequent replacement; Smoke from exhaust (blue or white); Engine burning smell; Oil light blinking or illuminated
Codes mentioned: P1326 (Knock Sensor Detection System; abnormal vibration consistent with rod bearing failure), P0304 (Cylinder 4 Misfire), Various misfire codes (cylinders 1, 2, 3, 4), High cylinder pressure codes
Repairs/costs cited: Metal shavings in oil pan discovered during diagnostics in multiple complaints. Dealers required authorization from Hyundai corporate before inspecting engine. Many owners forced into extended rental car periods (weeks to months) while vehicles sat at dealerships awaiting approval or diagnosis.
Recalls/TSBs owners mention: Hyundai class-action settlement (2021 Theta II settlement) provides extended 10-year/120,000-mile engine warranty and lifetime warranty for certain repairs. TSB #22-EM-001H (Engine Failure Campaign) references rod bearing issues. Campaign 953 (ECM & Cluster Update/Knock Sensor Detection System). However, owners report repeated denials citing that excessive oil consumption is a 'maintenance item,' not a defect. Warranty explicitly excludes second owners in most cases (original 60,000-mile limited warranty). Hyundai has refused to honor settlement terms in many complaints, claiming the root cause is not rod bearing failure or is attributable to owner maintenance gaps. Recall campaign 17V226000 (2013–2014 models) for similar engine failures, but many 2018 owners unaware of parallels. HMA declined engine replacement citing class-action settlement completions with unspecified problems.
Engine Stalling and Loss of Power
Engine unexpectedly stalls or enters limp mode while driving at highway speeds, causing sudden loss of motive power. Check engine light flashes and vehicle becomes difficult or impossible to restart. Safety-critical systems (power steering, power brakes) may also fail. Multiple incidents reported at 50–70 mph on highways and interstates, creating collision hazard.
When: Mileage range 11,653–149,000 miles; timing unpredictable after initial symptom onset
Symptoms owners cite: Engine stalls without warning at highway speed (50–70 mph); Vehicle enters limp mode (reduced power, cannot exceed 50 mph); Check engine light flashes (critical malfunction); Loss of power steering and power brakes; Audible engine knock or knocking noise from engine compartment; Engine misfires and sputtering before stall; Difficulty restarting after stall
Codes mentioned: P1326 (Knock Sensor Detection System), P0300 (Multiple-cylinder misfire), P0301 (Cylinder 1 misfire), P0302 (Cylinder 2 misfire), P0304 (Cylinder 4 misfire), High cylinder pressure codes
Repairs/costs cited: Repair costs for engine replacement range $3,000–$9,000+ out-of-pocket. One complaint cites $32,000+ in out-of-pocket expenses (rentals, repairs, inconveniences) due to repeated stalling incidents and dealership inaction. Multiple owners report vehicles towed 10–300 miles to dealerships and held for weeks to months awaiting diagnostics or approval.
Recalls/TSBs owners mention: Hyundai class-action settlement (Theta II, 2021) extends warranty to 10 years/120,000 miles for rod bearing failure. Campaign 953 (Knock Sensor Detection System update) intended to detect rod bearing failure via abnormal vibration. However, Hyundai has refused coverage in multiple complaints, claiming the stalling is caused by secondary issues (wrist pin failure, piston damage, cylinder scoring) rather than rod bearing defect. Some owners report Hyundai withholding engineering test data and refusing second opinions. Denied goodwill replacement despite vehicles being within extended warranty period.
Rod Bearing and Piston Damage
Internal engine damage involving rod bearings, pistons, wrist pins, and cylinders. Some failures confirmed as rod bearing failure under extended warranty; others diagnosed as downstream damage (piston damage, cylinder scoring, wrist pin damage) caused by underlying rod bearing defect. Metal shavings found in oil pan during teardown. Hyundai disputes causation in many cases to avoid warranty coverage.
When: Detected at mileage 45,000–150,000 miles; often discovered only after catastrophic failure
Symptoms owners cite: Audible engine knock (consistent with rod bearing failure); Metal shavings discovered in oil pan during diagnostic; Cylinder scoring and piston damage visible during teardown; Wrist pin damage or broken pins; Sudden loss of power and stalling; Check engine light with misfire codes; Engine unable to restart after failure
Codes mentioned: P1326 (Knock Sensor Detection System; designed to detect rod bearing failure), P0300–P0304 (Misfire codes indicating piston/ring damage)
Repairs/costs cited: Vehicles held at dealerships for 5+ weeks awaiting Hyundai engineering review. One owner reports dealership followed 'manufacturer's process' but Hyundai declined goodwill replacement despite documented piston damage and cylinder scouring.
Recalls/TSBs owners mention: Hyundai Theta II class-action settlement (2021) includes 10-year/120,000-mile warranty for rod bearing failure. TSB #22-EM-001H (Engine Failure Campaign) covers rod bearing defects. However, Hyundai has disputed multiple claims, arguing that damage observed (wrist pin failure, piston damage, cylinder scoring) is 'downstream' of rod bearing failure and therefore excludable. One complaint documents Hyundai stating 'lubrication not getting to the engine' rather than rod bearing defect, yet refusing to share supporting test data. Lifetime warranty for eligible vehicles under class-action settlement, but second owners often excluded. Recall campaign 17V226000 (2013–2014 Santa Fe Sport) recognized similar rod bearing and piston failures, but 2018 models sometimes treated as separate issue.
Oil Pan Leaks and Gasket Failures
Oil pan cracks near drain plug and defective oil pan gaskets cause oil leakage. One owner photographed visible crack in pan; others report low oil detected despite regular oil changes. Installation of new Hyundai filters with original washers sometimes preceded drain plug loosening and oil loss.
When: Oil pan crack discovered at 87,476 miles; gasket leaks occur across mileage range
Symptoms owners cite: Low oil level despite recent oil change; Oil spots under vehicle or visible oil trail on ground; Loose oil drain plug (unusual for careful owners); Oil dripping from area near oil pan drain
Repairs/costs cited: One dealership acknowledged pan crack after owner requested new drain plug washer and observed visual evidence; pan replaced same day.
Cylinder Head and Valve Train Failure
Burnt, cracked, or broken valves in cylinder head; carbon buildup on intake valves from excessive oil consumption. Valve train malfunctions including bearing or related defects. Carbon buildup accelerated by GDI (gasoline direct injection) design combined with excessive oil consumption.
When: Detected at 80,000–140,000 miles during diagnostics after stalling or performance degradation
Symptoms owners cite: Engine knocking and misfiring; Loss of power and limp mode; Check engine light with misfire codes; Engine vibration and rough idle; Difficulty accelerating
Codes mentioned: P0301–P0304 (Misfire codes indicating valve or combustion issues), P1326 (Knock Sensor Detection System)
Repairs/costs cited: High pressure fuel pump replacement ($1,150) performed after valve cover removal; owner disputes dealership claim that pump failure was unrelated to service work.
Recalls/TSBs owners mention: Hyundai attributed burnt valve to carbon buildup rather than Theta II oil consumption defect, potentially to avoid extended-warranty coverage. Owners contend Hyundai ignores the causal chain: excessive oil consumption → GDI deposits carbon on valves → valve overheating and failure.
Fuel Injector Malfunction and Gasoline Intrusion into Engine
Fuel injectors stuck open, causing gasoline to flow directly into oil pan and engine failure. Fuel smell and smoke from exhaust; large fuel quantities visible in oil pan on dipstick. One case involved uncontrolled fuel stall on highway with police order to evacuate vehicle due to fuel and fumes.
When: Failure at 14,210 miles (early in vehicle ownership) and 99,501 miles
Symptoms owners cite: Engine stalls with half tank of fuel (highway stall); Fuel coming out of exhaust pipes; Smoke from under hood; Check engine light illuminates; Fuel smell; Large amount of fuel visible in oil pan; Engine oil contaminated with gasoline
Repairs/costs cited: Vehicles deemed total loss by dealership in one case but repaired anyway. One owner at 14,210 miles offered one-month car payment to resolve $9,000+ engine failure.
Recalls/TSBs owners mention: Manufacturer suggested fuel injector replacement and oil drain/replacement, but offered no warranty coverage for engine damage. One case denied buyback request and offered one month car payment as full settlement.
Oil Consumption Test Denial or Inconclusive Results
Dealerships and Hyundai refuse to perform oil consumption testing despite owner requests, or testing is conducted but results are disputed or deemed inconclusive. Some dealerships claim test data cannot be shared with owners or mechanics. Testing protocols require multiple 1,000-mile intervals over 3,000 miles, during which vehicle may fail catastrophically.
When: Test requests made across mileage range 40,000–120,000 miles; delays of months common
Symptoms owners cite: Dealership refusing to perform test without prior engine damage; Test delayed weeks or months due to appointment unavailability; Results showing consumption of 1.7–4 quarts per 1,000 miles; Hyundai disputing test results or demanding additional cleaning before retesting
Repairs/costs cited: One owner waited 3+ years for Hyundai decision after multiple tests; finally received notice that vehicle was out of warranty. Another owner's vehicle sat at dealership for extended periods (1+ month) while Hyundai reviewed case.
Recalls/TSBs owners mention: Hyundai required oil consumption test as prerequisite for any warranty consideration but refused to commit to warranty coverage even after test confirmed excessive consumption. One dealership stated Hyundai would not provide test data for owner review. Hyundai has conditioned repairs on completion of expensive pre-tests (fuel injection cleaning) that do not resolve root cause. Multiple owners reported Hyundai denying coverage citing test results as inconclusive or claiming owner failed to maintain scheduled intervals despite documentary proof.
Synthesized from 157 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 11 most recent
The vehicle developed loud engine knocking and abnormal noise consistent with known Hyundai engine defects. The vehicle is unsafe to operate and has been retained at an authorized Hyundai dealership since October 25, 2025. Hyundai vehicles with similar engine failures have been documented to catch fire, including while parked. Despite the known defect pattern, the manufacturer is refusing…
This is a certified preowned vehicle. I am the second owner. I do my own maintenance. Currently this engine/vehicle has 64553 miles, I noticed it starting to use oil around the high 40k mile mark. There are no oil leaks. I have to add oil multiple times between oil changes and I just read that some of these can lock up and completely stop. I suspect this would be caused by people not checking…
2018 Hyundai Santefe 2.4L engine burned oil at a high rate and due to this caused 4k oil changes obsolete. The car need an oil change every 2k miles and still would have high build up. Hyundai claimed engine failure was due to gaps in the oil changes them being done around 4.5k miles in the start. Many people have had engine failures with these car and they are still selling them with the…
Driving on highway, when accelerator failed to maintain, the car started to jerk. After blocking traffic behind me, I was able to pull car over on the side of the busy highway, with smoke coming from hood. This was well after dark, and it was towed to a local and dependable mechanic. He had told me the engine was cracked. I am in the process of finding out if I am eligible for the extended…
I was on the highway and pressed the gas and the car started shaking. Wouldn’t go up in speed so I pulled off the highway and parked it. Checked the oil and it was almost empty even though I had an oil change about a month ago. Service center says it need a whole new engine at 108k miles. How is this possible? They say there were pieces of the valve in the fourth cylinder which also had lots of…
HIGH OIL CONSUMPTION: To the documented tune of 40 quarts consumed April17 - December 15, 2023, encompassing 24,116 driven miles. Hyundai America and this dealer knows all about this issue and is stalling on the remedy because it requires total engine replacement. Presently I am experiencing a P1326 engine knock sensor fault and I'm told by my mechanic a prospective catalytic converter failure…
The component that is malfunctioning is my engine. I took it into the dealership and they said I had cylinder scoring on my engine from excessive oil consumption. My safety was put as risk as my car threw itself into limp mode in the middle of the high way while going over 70 mph. I had to immediately pull over on the side of the highway and somehow get it back home while not being able to…
The contact owns a 2018 Hyundai Santa FE. The contact stated that while driving at 30 MPH, the was a burning oil smell permeating the interior of the vehicle. The check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the piston rings in cylinders one and three. After investigating the failure, the contact related the failure to NHTSA…
My 2018 Hyundai Santa Fe has a blown engine and will cost over $9000 to replace. Unfortunately my car is out of warranty at 120,000 miles. It has become known to me that this particular car, and thousands of others, has known problems with the engines. So much so, that a software update for a sensor was available in 2017, oil consumption issues and civil law suits have been highly publicized. I…
The engine is sucking oil faster than it normally would and could put me at danger. If it sucks up too much oil too soon I could lose control of my car in the winter and be the cause of an accident.
Had engine trouble with your 2018 Hyundai Santa Fe Sport?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2018 Hyundai Santa Fe Sport?
It's a documented issue but not catastrophic. 157 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 46 complaints that reported odometer mileage, most engine failures cluster between 58,000 and 115,000 miles, with the median around 97,000. A quarter of owners report trouble before 58,000; a quarter make it past 115,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2018/Hyundai/Santa Fe Sport.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.