2018 Ford Mustang engine problems

Filed Oct 30, 2026 · Engine · FL

I had engine coolant intrusion into the engine cylinders

Filed Oct 20, 2026 · Engine · AR

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.

Filed Oct 13, 2026 · Engine, Transmission · NY

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.

Filed Oct 2, 2026 · Engine · AL

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.

Filed Sep 11, 2026 · Engine · TX

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. On August 24, 2026, all four spark plugs and one ignition coil were replaced and a fuel/induction cleaning was performed. On September 10, the vehicle suddenly started with an extremely rough idle and produced a large cloud of white, sweet-smelling exhaust smoke. The check-engine light illuminated and the previous codes returned along with additional codes. The vehicle continued producing white exhaust smoke after several hours of diagnostic testing. Later that day, the engine shook violently while I was stopped at a traffic light and the tachometer fluctuated significantly. On September 11, the check-engine light returned and the previous diagnostic codes were again present. Firestone documented that coolant was present in the exhaust, that the coolant level was low again after coolant had been added the previous day, that the engine was burning coolant and producing white smoke, and that coolant was mixed with the engine oil. Firestone stated the engine may have a cracked head, failed head gasket, or internal engine crack and recommended complete engine replacement. The engine has now suffered a serious internal failure severe enough that the repair facility recommends replacement. The vehicle has exhibited violent shaking, unstable engine speed, repeated misfires, rapid coolant loss, coolant contamination of the engine oil, and coolant burning through the exhaust. I am concerned that continued operation could result in complete engine failure or sudden loss of engine power while driving, creating a significant safety hazard in traffic. Before September 10, the vehicle had never produced white exhaust smoke or experienced this severe shaking. I am reporting this as a potential safety defect involving the 2.3L EcoBoost engine.

Filed Sep 11, 2026 · Engine, Fuel system · TX

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.

Filed Aug 17, 2026 · Engine · AL

2018 WITH 118,000 MILES. Had to get a full block engine replacement due to coolant intrusion into the cylinders. This was diagnosed and replaced at a Ford dealership.

Filed Jun 25, 2026 · Engine · 56,000 miles · FL

The contact owns a 2018 Ford Mustang. The contact stated that while driving at various speeds, the engine sputtered with the check engine warning light illuminated. There was heavy white smoke coming from the tailpipe. Upon arriving at the destination, the vehicle hesitated to restart, and the contact observed a significant loss of coolant. The vehicle stalled while driving at various speeds. Upon inspection, the dealer confirmed coolant intrusion in cylinders #2 and #3, resulting in total engine failure. The manufacturer was notified of the failure and stated that the VIN was not under recall, and there was no warranty associated with the vehicle. The vehicle was repaired out-of-pocket by the dealer. The failure mileage was approximately 56,000.

Filed Jun 17, 2026 · Engine · 69,900 miles · TX

The contact owns a 2018 Ford Mustang. The contact stated that the air conditioning system failed to function as intended. Additionally, the contact stated that while accelerating from a complete stop, several unknown warning lights were illuminated, and the vehicle chugged and failed to accelerate as intended. The contact pulled over to the side of the road. The vehicle was towed to the residence. The contact stated that the vehicle was inoperable. The dealer was notified of the failure and informed the contact that there was no recall or warranty coverage for the vehicle. The contact was provided an estimate for the repair. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and suggested to purchase a new vehicle. The contact declined due to the sentimental value of the vehicle. The failure mileage was approximately 69,900.

Filed May 20, 2026 · Engine · GA

1. Component failed and availability for inspection: The engine assembly block failed due to a manufacturing defect known as "coolant intrusion into the cylinders." The vehicle and the defective engine are currently located at my residence and remain fully available for federal or manufacturer inspection upon request. 2. Safety risk: The safety of myself and others was severely compromised. Coolant entering the combustion chambers causes sudden, severe engine misfires across all cylinders, erratic power loss, and instantaneous stalling. Operating a vehicle where the engine can suddenly lose all power on high-speed roads creates an immediate risk of rear-end collisions and catastrophic traffic accidents. Furthermore, high-pressure internal coolant leaks pose an inherent risk of engine fires. 3. Problem confirmed by a dealer: Yes. The problem has been officially diagnosed and confirmed by an authorized Ford dealership service center, which documented internal coolant intrusion. 4. Inspected by manufacturer, police, or insurance: The component was inspected and verified by the vehicle manufacturer's authorized dealership technicians. It has not been inspected by the police or insurance representatives, as no crash has occurred yet. 5. Warning lamps, messages, or symptoms prior to failure: Prior to the diagnosis, the vehicle exhibited a "Check Engine Light." Currently, the vehicle is suffering from critical failure symptoms: the Check Engine Light is flashing constantly, the engine misfire codes are actively showing on all 4 cylinders, and the vehicle shakes violently at low RPMs (rough idling). These severe symptoms first appeared approximately 2 moths ago and have progressively worsened due to the coolant intrusion.