2018 INFINITI Q50 Engine Problems

Filing this complaint regarding a safety-related defect involving the turbocharger system on my 2018 INFINITI Q50. The vehicle has approximately 46,000 miles and is 8 years old. INFINITI/Nissan has acknowledged through its own Technical Service Bulletins (TSBs) that turbocharger failure on 2016–2018 Q50 3.0T vehicles is a known defect. Nissan’s documentation identifies issues such as turbo oil seal leaks, reduced engine power, smoke, and potential catastrophic engine failure, and provides an extended warranty of up to 10 years or 120,000 miles due to the safety risks associated with sudden power loss. My vehicle experienced turbocharger failure consistent with these known defects, resulting in loss of engine power, which presents a serious safety hazard, particularly during highway driving, merging, or intersections. Sudden loss of propulsion increases crash risk and endangers vehicle occupants and others on the road. In some cases, turbo failure can occur with little or no warning, further increasing risk. The failure was confirmed by INFINITI/Nissan service departments, and the vehicle remains available for inspection. CarMax insurance approved the engine repair, acknowledging mechanical failure; however, they declined to approve turbocharger repair specifically because INFINITI has issued a known TSB and extended warranty covering turbo failure, deferring responsibility to the manufacturer. Despite the vehicle being within the extended warranty limits, Nissan denied coverage, claiming the vehicle has a “branded title.” This claim is unsupported by VIN reports, the loan originator, and CarMax’s own title search prior to leasing all confirm the title is not branded. Nissan has provided no documentation supporting its assertion. Nissan N.A. reviewed and closed the matter despite the known safety defect and lack of evidence for the title claim. Represents a safety-related defect and improper denial of a manufacturer-recognized safety remedy, warranting NHTSA review.

NHTSA ID

11709489

Incident

Oct 4, 2025

Leak in the turbo causing oil to burn and create smoke from the exhaust

NHTSA ID

11704146

Incident

Dec 10, 2025

The serpentine belt on my 2018 Infiniti Q50 Sport became contaminated with oil immediately after dealer turbo replacement at the end of August 2025, causing the belt to slip, shred, and be pulled into the engine. This resulted in sudden loss of essential engine functions and poses a significant safety hazard. This failure was caused by improper repair at the dealership.”

NHTSA ID

11701863

Incident

Nov 11, 2025

The contact's son owns a 2018 Infiniti Q50. The contact stated that soon after purchasing the vehicle, there was an abnormal screeching sound coming from the brakes while depressing the brake pedal. There was no warning light illuminated. The contact's son took the vehicle to an independent mechanic to have the brake pads and rotors replaced. However, less than one month after the replacement of the pads and rotors, there was an abnormal grinding sound coming from the front passenger’s side brakes. The mechanic was notified of the issue, and the contact was informed that the brake calipers might also need to be replaced. The contact stated that while driving at various speeds, the engine temperature gauge indicated that the engine was hot(H), with white smoke coming from the exhaust pipes. The vehicle was taken back to the independent mechanic, but the mechanic was unable to determine the cause of the failure. The vehicle was taken to another independent mechanic and the contact's son was informed that the head gasket had failed, and an engine replacement was recommended. The dealer was notified of the failure, and the contact was informed that there were no recalls or warranty on the vehicle. The manufacturer was also notified of the failure and provided the same information as the dealer. The vehicle was not repaired. The failure mileage was approximately 88,000.

NHTSA ID

11693654

Incident

Aug 1, 2025

Mileage

88,000 mi

Within one month of purchase, the airbag warning light illuminated and has remained on continuously. A separate dealership later confirmed the airbag system is defective and may not deploy in an accident. This is a serious safety defect that was not disclosed to me at the time of sale. Additional Issues: •On July 14, 2025, I dropped the car off for prolonged starting issues. I was told the vehicle had six faulty fuel pumps/injectors. •I have not had possession of the car since July 14. •On August 30, 2025, I received an email from Nissan of Orange Park stating the car was “completed and ready.” When I called the next day, I was told the car was not at Nissan at all, but at Infiniti, with no clear repair status or timeline. Concern: This is a federal safety defect. I request NHTSA’s review and investigation into Infiniti/Nissan’s handling of defective airbag systems in this vehicle and the misleading communication surrounding repairs.

NHTSA ID

11686256

Incident

Jul 14, 2025

My car wouldnt start and when it did, it would start shaking and every time I accelerate, The speed wasnt going any faster but only the RPMs were

NHTSA ID

11681634

Incident

Aug 10, 2025

The contact owns a 2018 Infiniti Q50. The contact stated that while driving at an undisclosed speed, the "Low Oil Pressure - STOP", message was displayed, and the contact stopped driving the vehicle. The contact stated that while starting the vehicle, the engine was abnormally loud. The contact stated that the low oil pressure warning light was illuminated. The vehicle was towed to an independent mechanic, who diagnosed a failure with the timing chain. The vehicle was not repaired. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 107,000.

NHTSA ID

11638873

Incident

Jan 23, 2025

Mileage

107,000 mi

Turbos are starting to work and car is starting to consume anti freeze

NHTSA ID

11624689

Incident

Oct 1, 2024

I was driving down the highway and my car started to shut down and started to make a knocking sound inside the engine bay, putting at risk other drivers, so i turned on my hazards and pulled to the shoulder of the road,the car wouldn’t turn on so i called a tow truck. Took the car to dealer and stated engine is seized

NHTSA ID

11592525

Incident

Jun 1, 2024

My coolant reservoir kept on going empty, I took to dealer for service they replaced the radiator fan module and told me my engine was not porous. I was driving and my engine ended up stalling, turned off while I was driving in the freeway at a high speed cause me to almost lose control of my vehicle because everything stopped working. It looks like an inner rod failed possibly because of the coolant going into engine.

NHTSA ID

11517540

Incident

Feb 21, 2023

2/1/2023 we took our 2018 Q50 to the Infiniti dealership and service center. The engine was having issues, increased RPMs while simultaneously experiencing loss of power/stalling. This was experienced by both my wife and I. Infiniti's determination was the Mass Air Flow Sensor and told us the issue was not covered by the platinum, bumper to bumper extended warranty they sold us due to the warranty only covering mechanical issues, not electrical. The service tech was able to get costs waived as factory warranty covered such events to 75k miles. We picked the car up on 2/8/2023. On 3/18/2023 the car was again towed to the dealership. The intermittent issue that was thought to be the Mas Air Flow Sensor and electrical, hit suddenly and with such force the car would not run whatsoever and stalled out on a very busy 50 MPH Parkway and my wife had to maneuver her way to safety with cars flying all around her. No obvious sign of electrical mass failure, lights still on, etc. On 3/24/2023 I received a call and was told the engine needed to be replaced, the cost was $32k, and that the warranty’s fine print says that the warranty will only cover up to the fair market value of the car, which they determined to be about $21k. I’m responsible for their faulty engine & poor mechanical workmanship? I was sent pictures of debris and springs sitting in the bottom of the dropped oil pan and a separate photo clearly showing a disintegrating cam shaft / lower engine area adjacent to the oil pan. Catastrophic and very avoidable failure (this is not an engine in a military vehicle or motorsports vehicle). I believe the problem was never the Mass Airflow Sensor, it was the alloys used in this area of the engine that were failing. This failure is not the first for Infiniti (have been reading forums)

NHTSA ID

11513781

Incident

Mar 18, 2023

vehicle has porous block and lead to engine failure. many other VR30DDTT engine equipped vehicles are having the same issue some are being replace and others are not. this needs to be a major concern for nissan/infiniti as they are a fantastic brand but some of the customers of these vehicles are being left high and dry with no options

NHTSA ID

11510930

Incident

Feb 14, 2023

ON 6/13/2020 THE DRIVE BELT SHREDDED WHILE DRIVING UNDER 30MPH, UNDER LIGHT ACCELERATION. AT FIRST, THE BATTERY LIGHT ILLUMINATED ON THE INSTRUMENT CLUSTER, FOLLOWED THE CHECK ENGINE LIGHT. WHITE SMOKE BEGAN TO COME FROM THE ENGINE. THANKFULLY, I WAS NEARBY MY HOUSE AND MADE IT THERE SAFELY. FURTHERMORE, THE ENGINE OVERHEATED DUE TO A COOLANT HOSE BEING KNOCKED OFF BY THE SHREDDED BELT. ADDITIONALLY, THE WATER PUMP AND A/C COMPRESSOR FAILED. THE PULLEY TENSIONER ASSEMBLY AND BELT WERE REPLACED UNDER MANUFACTURER'S WARRANTY, ALONG WITH THE AFOREMENTIONED FAILED COMPONENTS. ALL WORK WAS DONE AT GRUBBS INFINITI OF GRAPEVINE, TX AND THE REPAIR TOOK EXACTLY THREE WEEKS TO FIX. THE FAILURE MILEAGE WAS 28,660. PREVIOUSLY, ON MARCH 6, 2019, INFINITI OF VAN NUYS, CA, TIGHTENED THE PULLEY TENSIONER ASSEMBLY DUE TO A SQUEAKING NOISE I WAS HEARING WHILE ACCELERATING. VEHICLE MILEAGE WAS APPROXIMATELY 10,000. I WAS INFORMED THAT IF I HADN'T HAD THIS ISSUE FIXED BEFORE MY DRIVE BACK TO TEXAS, MY DRIVE BELT COULD HAVE SHREDDED. AFTER THE DEALER ADDRESSED THE CONCERN NO FURTHER NOISE WAS HEARD AT ALL. THE DEALER ALSO INFORMED ME THAT THIS ISSUE IS KNOWN AND HAS BEEN DOCUMENTED IN INFINITI SERVICE BULLETINS. ALTHOUGH, THIS POSES A MAJOR SAFETY CONCERN AS THE VEHICLE COULD HAVE STALLED AT HIGH SPEED RESULTING IN AN ACCIDENT AND OR LOSS OF LIFE. I WORRY THIS ISSUE WILL HAPPEN AGAIN. TWO TIMES, TWO MANY!

NHTSA ID

11351917

Incident

Jun 13, 2020

Mileage

8,660 mi

VR30DDTT SERPENTINE BELT KEEPS SHREDDING

NHTSA ID

11316982

Incident

Mar 9, 2020

FROM START INTO THE WARM-UP, THERE IS A CONSISTENT WHORELING NOISE COMING FROM THE MOTOR.

NHTSA ID

11267524

Incident

Jul 4, 2019

Mileage

22,000 mi

THE SERPENTINE BELT MAKES CONSISTENT NOISE IN ALL TYPES OF WEATHER. ALREADY HAD THE DEALER REPLACE IT ONCE. NOISE CAME BACK AND THE DEALER NOW SAYS IT COULD BE THE TENSIONER PULLEY.

NHTSA ID

11267521

Incident

Jul 3, 2019

Mileage

22,000 mi

WHILE I WAS DRIVING MY INFINITI ON THE HIGHWAY MY SERPENTINE BELT SNAPPED 4 DIFFERENT TIMES WHILE IN MOTION. ALL WITHIN ONE YEAR. INCLUDING ME GETTING MY CAR BACK FROM THE DEALER AND THEM LETTING ME HAVE IT BACK THAT WAY. ALSO, THE TIRES ARE HORRENDOUS, FROM DAY ONE, THEY PULLED THE CAR LEFT OR RIGHT ON THE CAR. ALL THE SETTINGS WERE CORRECT ON THE CAR. I WANTED TO HAVE THE TIRES REPLACED, BY THE MANUFACTURER, AND THAT CAN BE DONE BECAUSE NO IT'S TO LONG AND EVERYONE TOOK TO LONG TO MAKE THINGS HAPPEN. NOT TO MENTION DUNLOP IS IMPOSSIBLE TO GET A HOLD OF.

NHTSA ID

11161699

Incident

Sep 17, 2018

Mileage

23,000 mi

THE CAR CAUGHT FIRE UNDER THE HOOD AND COMPLETELY BURNED UP IN THE PARKING LOT AS I WAS EXITING THE VEHICLE UPDATED 12/4/18*JB

NHTSA ID

11113316

Incident

Jul 18, 2018

Mileage

17,000 mi