Toyota Highlander engine failure problems

Filed Oct 29, 2026 · Engine · CA

My 2015 Toyota Highlander equipped with the 3.5L V6 engine developed an engine oil leak originating from the timing chain cover sealing area. On April 30, 2026, Kearny Mesa Toyota in San Diego, California, identified the leak during an inspection when the vehicle had a little over 100,000 miles. I am concerned that this condition may indicate premature failure of the timing chain cover sealing system and warrant investigation into a potential design or manufacturing defect. An engine sealing system should be sufficiently durable to prevent oil leakage under normal operating conditions. The occurrence of this problem at just over 100,000 miles raises concerns about the long-term reliability of this component and whether similar failures affect other vehicles equipped with the same engine. Although the leak was described as seepage or oily residue, it may worsen over time. Depending on its severity and location, leaking oil could contact hot engine or exhaust components, potentially causing smoke or creating a fire hazard. Continued oil loss could also compromise engine lubrication, lead to significant engine damage, or result in unexpected vehicle failure. These are potential safety risks associated with the condition, not claims that a fire or engine failure has already occurred. The oil leak was identified by a Toyota dealership during an inspection. The dealership’s diagnosis and related service records may be available for review upon request. Whether the manufacturer has formally investigated or acknowledged this condition as a defect is unknown. I respectfully request that the federal safety agency review this complaint alongside other reports involving timing chain cover oil leaks in 2015 Toyota Highlanders equipped with the 3.5L V6 engine. I ask the agency to determine whether these reports indicate a recurring premature component failure, whether the condition presents an unreasonable safety risk, and whether further investigation or corrective action is warranted.

Filed Oct 28, 2026 · Transmission · VA

The component that failed was the transmission. My safety was at risk because I was going uphill and the engine surged then the transmission seized, almost causing a rear-end incident with my family in the car. The dealer confirmed that the transmission has failed. No incident happened so only the dealer needs to be involved at this time. There were no warning lamps indicating to me that the transmission failed. Upon discovering that the transmission was not downshifting (based on the engine not downshifting uphill), I put the car into manual mode to determine if I could manually shift down or not, it would not downshift. Attempting to downshift to gears 4, 3, 2, or 1 was not possible, the lowest gear was gear 5 and the engine had no torque to get up the hill that it was seized on. The 2019 Toyota Highlander was serviced for the automatic transmission fluid at 100K miles and failed at about 120,450 miles.

Filed Sep 18, 2026 · Engine · GA

I purchased a 2013 Toyota Highlander in 2018 or.2019 with 64,000 miles. I was told to go 5000 miles before changes. My oil was gone many times when I did this. I reported this to Toyota dealership.I eventually stopped using them because they were hearing my problem. The complaints of lack of power and changing to 3000 mile oil changes wasnt heard. Now at 234 k.miles I have had to gix thr Catalytic converter twice, the oil pan gasket. The mechanic said there was metal in my oil and that engine failure was coming. Toyota has never acknowledged thier own oil consumption issues in their 4 cylinder engines.

Filed Sep 17, 2026 · Brakes, Electrical · 123,000 miles · CA

The contact owns a 2021 Toyota Highlander. While driving 20 MPH uphill, the messages "Engine Failure," "Brake Failure," and "Pull Over to A Safe Place, See Owner's Manual" were displayed, and several unknown warning lights illuminated. The contact turned off and restarted the vehicle, but the failure persisted. After a second restart, the message "See Dealer" was displayed with the check engine warning light illuminated. After a third restart, the vehicle was driving rough while the accelerator pedal was depressed. The vehicle was taken to the dealer. The manufacturer was notified of the failure by phone. The failure mileage was approximately 123,000.

Filed May 22, 2026 · Engine, Steering · TX

Hello, I am the Buyer of the subject Vehicle, Upon doing my research, I found out several reports stating that The subject vehicle's 2.4L engine has manufacturing defect, that causes Head Bolts to get stripped/melt down in to oil causing Engine failures and Life threating risk in the middle of the road.

Filed Feb 21, 2026 · Transmission · AZ

I was driving to a stop light when I heard a Raddle. Pull over and all the oil came out the engine. When I took it to the dealer they told me that the engine blew up. 14k repair that Toyota would not cover the repair.

Filed Dec 31, 2025 · Transmission · 55,000 miles · MA

The contact's wife owns a 2020 Toyota Highlander. The contact stated that soon after purchasing a new set of tires, the vehicle made an abnormal rattling sound upon acceleration. The vehicle was taken to a dealer for an oil change and tire rotation, and the contact was informed that no defect was found on the vehicle. As the failure persisted, the vehicle was taken back to the shop, where the tires were purchased. The contact was informed that there was no defect in the tires, and the failure might be related to the differentials of the vehicle. The vehicle was taken back to the dealer, where it was diagnosed with transmission failure. The manufacturer was then notified of the failure, and the contact was offered partial financial assistance towards the purchase of a new engine. The vehicle was not repaired. The failure mileage was approximately 55,000.

Filed Dec 16, 2025 · Brakes · MA

I own a 2021 Toyota Highlander Hybrid. The vehicle exhibits a dangerous braking surge defect. When braking during cornering or in stop-and-go traffic, the vehicle randomly surges forward even though the brake pedal is depressed. This creates a serious safety hazard and increases the risk of collision. On multiple occasions, this defect has nearly caused an accident. The last time it happened we were driving in stop and go traffic and the vehicle surged forward while depressing the brakes and the engine died leaving a red triangle on the dash. Toyota has acknowledged this condition through Technical Service Bulletin T-SB-0059-23, which applies to my vehicle. The bulletin involves reprogramming the brake actuator assembly control module to address the braking transition between regenerative and hydraulic braking. Despite this, Toyota has refused to apply hybrid system warranty coverage, misclassifying the defect as a conventional brake issue. My vehicle is available for an inspection. I contacted Toyota corporate, who initially responded but failed to provide follow-up or resolution. The defect persists after the bulletin was applied. Toyota’s refusal to cover the repair under the hybrid warranty leaves me with an unresolved safety defect. This complaint is intended to document the ongoing safety risk and Toyota’s failure to provide adequate remedy under warranty. I request the federal safety agency investigate this issue as a systemic safety defect affecting 2020–2022 Highlander Hybrid models.

Filed Sep 27, 2025 · Engine, Transmission · CA

On September 2, 2025, the vehicle’s Hybrid System shut down on cold start and the vehicle would not start. A dealer inspection reported coolant had entered cylinder #4, allegedly causing the engine block to warp, the cylinder head to crack, and the head gasket to fail. This was a sudden catastrophic engine failure on a five-year-old vehicle with no prior overheating warnings, no dashboard alerts, and no performance issues in the days leading up to the failure. It is highly unlikely for an engine block to warp without sustained overheating, yet the failure occurred on a cold start. The dealership itself described this as a “premature failure” in their service report. At approximately 26,000 miles, the vehicle’s coolant thermostat failed and was replaced under warranty. If the thermostat stuck closed even briefly, the engine could have experienced one or more silent overheat events that never registered on the dashboard. In aluminum blocks, even short bursts of high localized heat can create latent distortion that doesn’t cause immediate problems but can eventually lead to catastrophic failure years later. Safety Risk: – Vehicle became disabled suddenly without warning. – Engine failure occurred without overheating symptoms, creating risk of sudden shutdown during use. Problem Confirmation: – Engine failure confirmed by a Toyota-authorized dealer. – Dealer service report explicitly called this a “premature failure.” Warning Lamps / Symptoms: – A check engine light appeared briefly three days before failure, then cleared on its own. – No overheating warnings or drivability issues were observed prior to failure.

Filed Sep 11, 2025 · Electrical, Engine · IN

Formal Complaint to the federal safety agency – Summary I am submitting this formal complaint regarding repeated mechanical and electrical failures involving my 2017 Toyota Highlander, purchased as a Toyota Gold-Certified vehicle with an extended Platinum Warranty. Despite strictly following Toyota’s maintenance guidelines and using only certified dealerships for all services, the vehicle has become inoperable multiple times, requiring five separate tows and resulting in repair costs exceeding $10,000. In June 2025, a Toyota dealership replaced the engine after diagnosing a warped head due to water pump failure. Following this, the vehicle began experiencing repeated charging system failures and electrical malfunctions. Multiple components—including the alternator, battery, and sensors—were replaced at another Toyota dealership based on ongoing issues, but the problems persisted. On September 2, 2025, a Toyota technician identified a missing ground wire nut as the likely root cause of these electrical failures. He confirmed the issue originated during the engine installation and that the unsecured ground caused system malfunctions. After repairs, the vehicle was again returned with a loud engine knocking noise, later traced to an improperly secured component from a prior repair. These events have raised significant concerns for the safety of myself and my family. Improper installation of major components and misdiagnosis by certified service providers have led to hazardous driving conditions, unexpected vehicle shutdowns, and unnecessary costs. I am requesting that the federal safety agency investigate this matter for potential safety defects related to improper engine installation, grounding failures, and faulty electrical diagnosis by certified Toyota service centers. Documentation, invoices, and repair records are available upon request. Thank you for your attention to this critical safety issue.