2018 Ford Mustang: engine failure

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 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 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 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 Apr 17, 2026 · Engine · CA

A check engine light turned on and the vehicle was taken to a local dealership. The check engine light was for an engine misfire and was diagnosed further. There was an engine failure due to coolant entering the system. Upon further research, I learned this is a common issue for 2016-2020 Ford Mustangs and it is due to a faulty engine design. The dealership is recommending a new engine install with a price tag of over 13,000 despite this being known to happen because of a badly designed engine with these cars.

Filed Mar 20, 2026 · Engine · OK

When driving the car, the engine temperature light came on, pulled the car over to let it cool down, when cooled, drove home and looked in the engine compartment, found the coolant reservoir empty, filled it with proper coolant, next day the engine light came on, took to O'Reilly auto parts to scan code, problem was Cylinder #3 misfire, changed out spark plug, noticed that coolant reservoir was low again, searched internet for possible causes when found that many people are having the same issue, turns out Ford manufactured the 2.3L engines with a faulty design where the cooling leaks into the cylinders "Coolant intrusion". the fix that Ford has established for this issue is to replace the engine with a "long block" version, but will not issue a recall. We have contacted Ford and explained the issue, but they will not repair. This should not be happening to a car with only 27,000 miles. now we are stuck with a car we can't drive and don't have the extra $5,000 plus dollars to replace the engine!

Filed Jan 28, 2026 · Engine · MI

Engine stopped working while traveling down a major interstate. Upon further inspection, the engine (EcoBoost) was defective and had to be replaced at my expense. This type of engine is known to have a manufacturing defect and was barely out of warranty. Ford would not replace the engine. Thank you

Filed Nov 28, 2025 · Engine · TX

My 2018 Ford Mustang EcoBoost experienced sudden engine failure at 70,915 miles. The dealership documented misfire codes P0300, P0301, and P0316, which match the known 2.3L EcoBoost coolant-intrusion defect. This defect causes loss of power, rough operation, misfires, and potential stalling, creating a safety risk during driving. Ford Customer Relationship Center instructed me that the dealership must escalate the defect to the Regional Field Service Engineer. However, the dealer refused to do so, leaving the failure unresolved. This appears to be part of a widespread safety-related defect involving 2.3L EcoBoost engines, with risk of sudden loss of power, stalling, and internal engine failure

Filed Oct 2, 2025 · Engine · FL

There is a coolant intrusion on my vehicle, which resulted in either cracking the engine block or head gasket. In turn, this has caused a costly repair on a car with only 56,000 miles on it. Ford is aware of the issues with these engines and the seals on them. It’s a 2018 Ecoboost! It also happened to my mom’s Ecoboost around the same mileage. This isn’t normal and Ford is literally turning a blind eye to a very serious issue which results in total engine failure. On top of that the repair for this issue is costing $12,000 to repair at the dealership. This is absolutely absurd for a company as big as Ford, to build a faulty engine and then not offer any support/recalls to help all of those affected by it, including me.

Filed Aug 21, 2025 · Engine, Transmission · TN

For roughly 4mths beginning in April 2025, my 2018 Ford Mustang Ecoboost has been suffering from a sporadic misfire, with it the system reporting the misfire and the check engine light coming on, the Ford App identifying the misfire occurring. It was initially repaired with replacing all spark plugs, ignition leads. The sporadic misfire would continue to occur, Ford dealership kept the car for 2 days in late July, took everything apart said they were unable to replicate the misfire, cleared the codes (P0303 being the main one that appears consistently) and said to come back if it occurred again. Roughly 2 weeks later the issue occurred again, took the vehicle back to Ford where they kept the car for 2 days, went through the same process and could not replicate the issue. They dug deeper into the issue and found that the coolant would not hold pressure and with the use of a video scope found that the Intake Valve had fractured and was leaking coolant into the engine as well as distributing multiple shards and pieces of metal from the Valve Intake Fracture. Informed me that the only option was to replace with a new engine and turboboost. They reviewed and found that there were no recalls related to this issue for this vehicle. After undertaking my own research, I found this to be a known issue for Ford and that roughly 100k vehicles had been recalled starting with the 2020 vehicles for the same issue. The out of pocket expense is around 14k, and the vehicle is currently waiting on a replacement engine to arrive. Currently Ford are not offering any assistance in the cost of the replacement, been though they have been servicing the car since 2020 and it is regularly maintained per their guidelines of vehicle needs based on the mileage driven.

Filed Jul 14, 2025 · Engine · 18,000 miles · FL

The contact owns a 2018 Ford Mustang. The contact stated while driving at an undisclosed speed, the engine seized. There was no warning light illuminated. The vehicle was pushed to a nearby independent mechanic however, the vehicle was not diagnosed. The vehicle was then towed to another independent mechanic where it was diagnosed with a ruptured cylinder #1, causing engine failure. The contact was informed that the engine needed to be repaired or replaced. The vehicle was repaired. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 18,000.