2018 Ford Mustang

I had engine coolant intrusion into the engine cylinders

The engine has a head gasket defect that leaked coolant into the engine causing misfires and requires a very expensive repair for a defect that came with the engine when it was made. Two Ford dealerships have inspected and confirmed the issue. The car threw codes six months ago and we immediately stopped driving it and had the dealership inspect the problem. We have not fixed it yet as the repair is estimated at 6,000. Parts and labor. It is available for inspection. This seems to be a very common issue with this vehicle. We replaced the fuel rail, spark plugs, and have had an independent inspection by a non affiliated repair shop for a similar price.

The 2.3L EcoBoost engine failed due to coolant leaking into the combustion chambers. The dealer found coolant present in cylinders 1 and 4, the cylinder 4 piston washed, and vertical scoring on the cylinder 4 wall. The dealer's recommendation is complete engine replacement. Yes, the engine is available for inspection. The vehicle is currently at the Ford dealership and the engine has not yet been replaced. Coolant entering the cylinders causes misfiring and loss of engine power. The vehicle shook on startup and ran roughly, and the misfire was intermittent and unpredictable. A sudden loss of motive power while driving in traffic or at highway speed is a crash risk to me and to other drivers. Coolant loss into the cylinders also reduces the coolant available to cool the engine, creating a risk of overheating. The vehicle is currently not safe to drive. A Ford dealership has reproduced the issue and confirmed it. The technician retrieved stored codes P0304 and P0316, removed the spark plugs and coils, and borescoped the cylinders. A cooling system pressure test was performed and the vehicle was allowed to sit, after which borescope inspection confirmed coolant in cylinders 1 and 4. This was the second visit for the same concern. At the first visit, in August 2026, the dealer replaced all four spark plugs and the cylinder 4 ignition coil, and the misfire returned within weeks. The vehicle has been inspected by an authorized Ford dealership. A goodwill assistance case has been opened with Ford Motor Company and Ford has offered partial coverage of the repair. No police or insurance inspection has occurred. The check engine light illuminated and the vehicle shook on startup and ran roughly. These symptoms first appeared in August 2026 at approximately 32,600 miles. The dealer replaced spark plugs and an ignition coil at that time and the symptoms returned within weeks. Check engine light was not illuminated at the second visit, but codes were stored in memory.

Check engine light came on Sunday night. Monday had AutoZone check the codes - indicated misfire on two cylinders recommended spark plug replacement - Spark plugs purchased with intent to change Tuesday evening- Tuesday morning -Engine overheated on the way to class added more coolant - got the vehicle home and towed to local Ford Dealership the next day to learn that the coolant was leaking into the engine due to head gasket failure. Ford said the engine needed to be replaced.

The electrical components in the vehicle stopped functioning - for the lights on the interior the overhead stopped working on and off and then dimmed until one day never came back on. At the same time the sensor for cross traffic alert became buggy and then not functional which made all my safety features and cruise control not work. Now I have a TPMS sensor and check engine light with nothing serious wrong

While driving at highway speeds passenger door spontaneously opened. Passenger was not touching or near latch. Has happened 3 times. Ford states no recall. Looking online seems to be a known issue.

I own a 2018 Ford Mustang EcoBoost convertible and am reporting persistent spider activity that has become a recurring driver-safety concern. Spider activity occurs on or around the vehicle essentially every day. I routinely see multiple spiders and webs on the windshield, hood, doors, roof, trunk, sides, and around both exterior mirrors. Spiders repeatedly build webs between the doors/body and both mirror housings, and I have seen spiders crawl out from behind the mirrors numerous times, especially the driver-side mirror. I also find web strands inside the passenger compartment. On three occasions, a spider rebuilt a large web across the driver’s-seat entry area after I removed it. On Sept. 10, 2026, after a commercial car wash earlier that day, I had about six spider sightings within roughly 10 minutes. While driving, I saw one crawl up the hood and disappear near the base of the windshield. Shortly afterward, a sizable spider appeared INSIDE the windshield directly in front of my face, apparently coming from where the dash meets the windshield. I have severe arachnophobia and had an immediate panic response. I was fortunate to reach a nearby parking lot and stop without crashing. During the same period, I saw two spiders on the trunk, then another crawling across the interior headliner directly above me, followed by another emerging from the driver-side mirror. I am becoming genuinely afraid to drive this vehicle. This is not a cosmetic complaint. Spiders repeatedly appear in the driver’s immediate environment and create a risk of sudden distraction, involuntary panic, abrupt steering/braking, loss of lane control, and a crash. The car is normally kept closed and I rarely lower the convertible top because of this problem. I am not asserting a specific defect or entry path. I am asking NHTSA to review similar complaints and determine whether a vehicle-design condition may be contributing to persistent spider habitation or intrusion into the driver’s area.

I own a 2018 Ford Mustang EcoBoost Premium with the 2.3L EcoBoost engine. The vehicle initially developed a check-engine light and was diagnosed with P0303 (Cylinder 3 misfire), P0316 (startup misfire), and P018C (fuel pressure sensor circuit low). On August 24, 2026, all four spark plugs and one ignition coil were replaced, and a fuel/induction cleaning service was performed. The P018C repair was declined at that time. On September 10, 2026, the vehicle started with an extremely rough idle and produced a very large cloud of white, sweet-smelling exhaust smoke. The check-engine light came on. The original codes, including the misfire codes, were present along with additional codes. The vehicle underwent approximately three hours of diagnostics and road testing. The codes were cleared, and afterward only P018C returned. Testing reportedly did not identify a head-gasket leak, but visible white smoke was still coming from the exhaust when I left the repair facility. Possible coolant intrusion involving the turbocharger was discussed, but the source was not confirmed. Later that day, the vehicle would not crank in Park but started in Neutral. While driving home, the engine began idling so violently at a traffic light that the entire vehicle shook and the tachometer fluctuated significantly. Before September 10, the vehicle had never produced white exhaust smoke, never shaken violently at idle, and always started. The repair facility attempted to inspect the cylinders with a borescope, but both of its borescopes were not functioning. I am concerned about possible coolant intrusion or another engine defect because of the Cylinder 3/startup misfire history, heavy white sweet-smelling exhaust, and severe intermittent rough running. The cause has not yet been confirmed, and I am concerned about possible engine failure or loss of power while driving.