About two months after purchasing my new 2026 Toyota Grand Highlander Hybrid, I noticed the air conditioning had stopped cooling. I did not notice any impact, so I do not know exactly when the damage occurred. I drive normally on public roads and do not go off road. The vehicle had approximately 7000 miles when the problem was found. There were no warning lights or messages. The only symptom was the AC blowing warm air, which I first noticed around September 25, 2026. Tansky Sawmill Toyota in Dublin, Ohio inspected the vehicle on [date] and found the AC condenser had been punctured by a rock or road debris. The dealer classified it as road damage and declined warranty coverage. The repair cost $2005.03. The damaged part is / is not available for inspection. I have the repair order and photos of the damage. The Grand Highlander's grille has large openings with no protective screen in front of the heat exchangers, so ordinary road debris can strike them directly. In my case the condenser was hit, but the radiator and hybrid inverter radiator sit in the same exposed area, and damage to those can cause coolant loss and loss of propulsion while driving. That puts drivers and others on the road at risk. I believe this is a design defect and ask that my complaint be considered as part of Defect Petition DP26006.
Toyota Grand Highlander overheating problems
14 of the 379 owner complaints about the Toyota Grand Highlander describe engine overheating, most of them for the 2025 model year.
- owner complaints
- 14
- worst model year
- 2025
By model year
- 20263
- 20258
- 20243
Often reported together
What owners say
Engine temperature overheated during long idle on an out of town event. The vehicle put in park and engine running in idle with AC running. Vehicle coolant temp reach high mark in the red area. Vehicle temp alarm gave a warning to shutdown. I estimated the car idle time 40 min due to traffic accident ahead. The incident occurred on 9/11/26. The car was taken to dealer 9/17/26 for checkup/diagnose the issue. Dealer stated, they could not duplicate the issue. But they did my find the vehicle computer log, the engine registered high temp.
The air conditioning system on my 2024 Grand Highlander failed due to a punctured AC condenser caused by road debris passing through the front grille during normal driving. The front fascia has large open apertures with no protective mesh or screening, leaving the condenser, radiator, and other heat exchangers directly exposed to rocks and debris. The condenser face shows multiple debris strikes, with one impact puncturing the core and causing complete refrigerant loss and AC failure at approximately 62,000 miles. The vehicle worked normally when parked and the AC was completely dead one week later due to the slow refrigerant leak from the puncture. Diagnosis was performed by [XXX] Toyota in [XXX], which confirmed the puncture was caused by road debris. The repair is not covered under warranty or my extended service contract because it is classified as outside damage, leaving owners to pay out of pocket for a design vulnerability. This is the same failure mode described in open ODI Defect Petition No. XXX covering 2024-2026 Grand Highlander vehicles. The same unprotected grille openings expose the engine radiator, meaning the identical debris path can puncture the radiator and cause coolant loss, engine overheating, and sudden loss of propulsion in traffic. The grille design leaves critical cooling components unreasonably vulnerable to everyday road debris. Photos of the punctured condenser and the dealer's written diagnosis are available. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
A piece of road debris/rock struck the radiator/heat exchangers in my 2025 Toyota Grand Highlander Hybrid that immediately damaged the radiator/heat exchangers to result in coolant leakage and sudden loss of propulsion and terminated the engine from moving and required a tow to a Toyota dealer and thus a replacement of the heat exchanger/radiator. It came apparent from their experience that the design of the front-end grill has large, open apertures and no protective screen between the grill and the vehicle’s heat exchangers. Had to file an insurance claim under comprehensive coverage that required me paying a deductible for repairs and NOW stress in future driving experiences.
The contact owns a 2025 Toyota Grand Highlander. The contact stated that while driving approximately 35 MPH, another vehicle struck a rock, and the rock went through the front grille of the vehicle and punctured the inverter radiator, causing a coolant leak and a loss of motive power. The message "Hybrid System Malfunction" was displayed following the loss of motive power. The vehicle was towed to a dealer, where it was diagnosed and determined that the inverter radiator had sustained a puncture and needed to be replaced. The vehicle was repaired. The contact associated the failure with the federal safety agency Action Number: DP26006 (Engine and Engine Cooling). The failure mileage was approximately 14,300.
The contact owns a 2025 Toyota Grand Highlander. The contact stated that while driving 60 MPH on the highway with a three-year-old child in the vehicle, the message "Pull Over Immediately and Shut Off the Vehicle" was displayed. The contact was able to pull over to the side of the road and waited for a tow truck in hot weather. The vehicle was towed to a dealer, where it was diagnosed and determined that the radiator was punctured by a rock that had gone through the front grille and caused a coolant leak. The dealer determined that the radiator needed to be replaced. The vehicle was scheduled for the repair. The contact informed the dealer that the failure was a common issue associated with the federal safety agency Action Number: DP26006 (Engine and Engine Cooling); however, the dealer informed the contact that the manufacturer was not aware of the issue. The failure mileage was approximately 12,200.
I am writing to formally report a potential safety defect involving the front grille design of my 2026 Toyota Grand Highlander Limited. Fortunately, my vehicle has not experienced any damage or mechanical failure related to the grille at this time. However, after examining the design of the front grille and the components located directly behind it, I have serious concerns that the relatively large grille openings may allow rocks and other road debris to pass through and strike critical cooling components, including the radiator and other heat exchangers. My concern is particularly related to the potential consequences of such an impact. If road debris were to damage a cooling component, it could result in coolant loss, overheating, warning messages, reduced vehicle performance, or potentially loss of propulsion. If this occurred while traveling at highway speeds, it could create a significant safety risk for the vehicle occupants as well as other motorists. I understand that the federal safety agency is currently reviewing concerns regarding the front grille design of 2024–2026 Toyota Grand Highlander vehicles. I would like my vehicle and this concern to be included in the federal safety agency’s review. I believe this issue warrants further evaluation because the concern exists even before an actual failure occurs. A safety defect should ideally be identified and addressed before owners experience a failure that could potentially create a hazardous situation while driving. I respectfully request that the federal safety agency investigate whether the front grille provides adequate protection for the critical cooling components behind it and determine whether Toyota should provide a protective screen, revised grille design, or another corrective measure. Again, I want to emphasize that I am reporting this as a potential safety defect. My vehicle has not suffered damage or experienced a failure at this time. I am submitting this complaint proactively because I believe the design presents a foreseeable risk
My wife was driving and a small rock passed through the front grill puncturing the radiator and causing her check engine light to come on. Within 5 minutes the coolant leaked out and the car was undrivable. We took it to Bredemann Toyota in Park Ridge who replaced it.
Radiator issue summer of 2025, when in back to back traffic at low speeds my vehicle overheated at a stand still took vehicle in to dealership with no real answers. The following summer 2026 same scenario but the engine was smoking. Took into dealership and they stated the connection for the radiator fan was disconnected which meant it was not colling the engine. A month later the AC is blowing hot air when AC is set to the coolest setting, scheduled another appt with dealership likely another radiator issue. Fuel gauge inaccuracy. Manual states 17 gallon tank capacity but my car states empty and can only fill the tank with 14 to 15 gallons. Dealership had no help and stated it does that to protect the hybrid engine. Transmission shifting issues, in the summer hotter temperatures I notice at times the transmission has difficulty shifting in lower gears and really revs up the RPMs to shift sometimes. At times the the transmission shift is jerky or harsh when going speeds form 20- 40 mph.
While driving my 2024 Toyota Grand Highlander Hybrid AWD at highway speed with only 16,755 miles on the vehicle, multiple warning messages suddenly appeared, including warnings related to the engine, hybrid system, AWD system, and other vehicle functions. The vehicle instructed me to pull over immediately and significantly reduced power output, making it difficult to maintain highway speed and safely maneuver through traffic. I was able to reach the shoulder and had the vehicle towed to a Toyota dealership. The dealer diagnosed a punctured radiator caused by a rock or similar road debris that allegedly passed through the front grille and struck the radiator. The dealer confirmed that coolant loss from the puncture triggered the vehicle's protective reduced-power mode. This failure created a significant safety risk. A sudden loss of power while traveling at highway speed increases the risk of rear-end collisions and other accidents, particularly in heavy traffic where drivers may not expect a vehicle to rapidly decelerate. There were no warning lights, messages, leaks, drivability concerns, or other symptoms before the incident. All warnings appeared suddenly at the time of failure. Toyota has declined warranty coverage, classifying the damage as a road hazard. However, I believe this may indicate a design defect. I have identified numerous reports from other GH owners describing nearly identical failures involving rocks penetrating the radiator through the front grille, often at relatively low mileage. These reports suggest the radiator may be inadequately protected from ordinary roadway debris. My concern is not simply radiator damage, but that a small piece of road debris encountered during normal driving can disable a critical component and cause the vehicle to enter a severe reduced-power mode at highway speed. I request that the federal safety agency investigate whether the front grille and radiator protection design of the Grand Highlander creates an unreasonable safety risk
Related recalls
No recalls on record for this model year.
Questions about the Toyota Grand Highlander overheating
Which Toyota Grand Highlander years have engine overheating problems?
The model years with the most reports are 2025 (8 complaints), 2024 (3 complaints) and 2026 (3 complaints).
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