NHTSA Complaint #11638682 — 2018 HONDA ACCORD

My 2018 Accord Sport 1.5 blew the head gasket at 118,000 miles. I've always taken good care of the car—it's never been damaged or abused, and I’ve used the highest quality engine oil for every oil change at 10k miles, even though Mobile claims it can last up to 25k miles. One morning, on my way to work, I started experiencing a misfire as I pressed the gas when the light turned green. Suddenly, the car lost all power, and I had to turn on my hazards and coast to the shoulder. After turning off the engine and waiting a few minutes, I was able to start it again and barely make it to work. I initially suspected a bad spark plug or coil pack, so I replaced all four plugs and coil packs. The fix worked for a day, but then the misfiring returned. The code was reading “cylinder 4 misfire,” so I decided to take it to Honda for a diagnostic. They called me after the test and informed me that the head gasket for that cylinder had blown, quoting me $5,000 for the repair. I refused to pay that and decided to tackle the job myself instead. The dealership wanted to drop the engine and disconnect everything, even suggesting a transmission fluid change, despite the fact that I’d had it serviced just 15 to 20 thousand miles ago. After doing some research, I found a replacement head gasket for only $35 and went ahead with the repair. Everything was going smoothly until I hit a snag with the crankshaft pulley nut, also known as the harmonic balancer nut. Despite numerous attempts, it just wouldn't budge. I tried using a 1,200 ft-lbs 1/2” pneumatic impact, then switched to a 1,600 ft-lbs 1/2” Milwaukee battery impact, and even got a pulley lock to secure it in place with a breaker bar. Unfortunately, the pulley is poorly made! When we over-torqued it, we ended up breaking the pulley even more. We also tried a torque multiplier, which only made things worse. Now, the only way to get that stubborn nut off is with a 2,000 ft-lbs impact, but I still haven't managed to break it free.