2018 Infiniti Q50 engine problems

Filed Jan 7, 2026 · Engine, Fuel system · CA

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 the federal safety agency review.

Filed Dec 10, 2025 · Engine · AL

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

Filed Nov 28, 2025 · Engine · GA

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.”

Filed Oct 15, 2025 · Brakes, Engine · 88,000 miles · NY

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.

Filed Sep 10, 2025 · Airbags, Engine · FL

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 the federal safety agency’s review and investigation into Infiniti/Nissan’s handling of defective airbag systems in this vehicle and the misleading communication surrounding repairs.

Filed Aug 19, 2025 · Acceleration, Engine · AZ

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

Filed Jan 27, 2025 · Engine · 107,000 miles · CO

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 federal safety agency Hotline for assistance. The failure mileage was 107,000.

Filed Nov 12, 2024 · Engine · KY

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

Filed Jun 4, 2024 · Engine, Steering · CA

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

Filed Apr 17, 2023 · Engine · CA

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.