2018 Honda Accord Hybrid engine problems

“While driving on a bridge at under 20 mph, the vehicle's head gasket failed, causing the engine to overheat and coolant to leak from within the engine. The vehicle threw diagnostic trouble code P2601 and immediately entered "limp mode," severely cutting engine power and vehicle speed. Because this happened on a bridge with no shoulder to safely pull over, the sudden loss of power created a serious safety hazard — the vehicle could not maintain a safe speed or keep pace with surrounding traffic, increasing the risk of being struck by other vehicles. The vehicle was taken to a Tampa Honda (11000 N Florida Ave), where the failure was confirmed to be a blown head gasket that allowed coolant to leak into the engine cylinders. The head gasket and related components were replaced at a cost of approximately $5,000 to restore the vehicle to safe operating condition. The failed component is no longer available for inspection in its failed state, as replacement was required to make the vehicle drivable. No dealer, manufacturer representative, police officer, or insurance adjuster has inspected the vehicle; only at Tampa Honda facility that performed the repair diagnosed…”

“On 2-252026 my wife and I were driving on highway I-15 in California when the car started to accelerate, decelerate and jerk and the engine light came on. It was very scary because we were on a major highway driving around 60 MPH and cars were behind us when the deceleration happened. We could have been hit by cars traveling behind us or either we could have caused a major accident. We had to get off the highway and have the car towed to Honda for assessment. There was no engine light warning or service warning from Honda prior to this happening, it just randomly happened. The car was repaired at a Honda dealership and they said there was a leaking head gasket on cylinder number 4. When we looked up information regarding this head gasket failure we saw that other Honda cars have had the same problem and Honda is currently involved in lawsuits regarding this leaking head gasket on cylinder number 4.”

“While driving on the highway at approximately 65 mph with my child in the vehicle during rush-hour on May 21, 2026, my 2018 Honda Accord Hybrid Touring (105,746 miles) suddenly dropped speed, and began backfiring and stopped responding to the gas pedal. The check engine light flashed and the vehicle ran rough. I activated emergency flashers and drove slowly to the shoulder. Sunnyvale Honda (Sunnyvale, CA) diagnosed coolant intrusion into one of the cylinders and head gasket failure. The vehicle had never overheated and showed no prior warning signs. All maintenance was performed at Honda dealerships per the maintenance minder schedule. The dealership performed a head gasket repair costing $7,500+ out of pocket. On the first highway drive after pickup, again with my children in the vehicle, the identical failure occurred: backfiring, complete loss of throttle response, vehicle unable to exceed 48 mph with the accelerator fully depressed. The repair did not resolve the defect. The vehicle is currently back at the dealership for further investigation. This failure created an immediate safety hazard on both occasions: sudden loss of speed on highway with no…”

“I am writing to file a formal complaint regarding my 2018 Honda Accord [VIN# [XXX] ] concerning what I believe to be a defective cylinder head or head gasket — an issue I have since learned is widely reported within the Honda owner community and is currently the subject of active class action litigation. Beginning at approximately 89,000 miles, my vehicle began experiencing episodes of engine rumbling followed by sudden shutoff. These episodes occurred two to three times before I brought the vehicle to an authorized Honda dealership at approximately 99,000–105,000 miles for diagnosis. At the dealership, I paid for a diagnostic inspection. I was informed that the technicians could not identify the root cause without performing a full engine pull and internal inspection, which they estimated would cost several thousand dollars — with an additional cost of $5,000–$8,000 if the diagnosis confirmed a cracked cylinder head or failed head gasket. Unable to absorb this expense, I did not authorize the repair. In an effort to keep the vehicle operational, I worked with independent mechanics and took the following corrective measures: replacement of spark plugs and…”

“Over the past several years, there have been multiple instances where I or my wife are driving on the highway and the engine light comes on or starts flashing, and I am unable to go faster than 50 miles an hour, and the engine itself feels to be underpowered. We have taken it to the dealership for repair at least five times over the past five years and in each case they have attempted to do a repair and said the issue has been resolved, but the issue continue. At at least one of those visits, they have diagnosed the issue as an engine misfire issue. The issue has intensified from the initial symptoms, (which were as I described, but resolved by turning the car off, waiting 30 seconds to a minute and then turning the car on again) to how it is now: in addition to the check engine light, every other light and warning system has gone off when driving on the highway and the engine was unable to go faster than 40 miles an hour, and it does not resolve by restarting the car. The dealership and Honda America’s main phone line have as of yet been unable to give me a clear answer as to why this is happening or whether it can be fixed. A sudden drop in speed and power on…”

“The car loses power. It starts as a misfire on cylinder 2 (P0302 code) and the engine starts to shutdown (or goes into a safe mode with no power). The result is loss of speed which creates a safety hazard especially on highways. This has happened multiple times and the car has been in the shop 4 times for this issue. We have to pull off the road, turn the car off, sit for a minute and restart the car. It will then run ok. This has happened during acceleration and when just trying to keep speed on an incline. The dealership has not been able to identify an issue. The head gasket was replaced in April 2025 because they thought there was a pin hole that was causing oil to push into the cylinder. The misfire continued to happen. It was in the shop on October 2025 and they found nothing wrong with the spark plug, induction coils, gas feed. Therefore no understanding of the root cause.”