2018 Ford Mustang

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

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.

My engine began experiencing misfires at around 40,000 miles. They were on and off. The check engine light would pop up and go away for around a month. Then the vehicle began having a rough start and check engine light would not go away. I sent the vehicle back to the dealer where they determined that my engine was having misfires due to a coolant leak into cylinder one, stemming from a poor engine design. The engine needed to be replaced. The repair was covered under my warranty.

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.

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.

I own a 2018 Ford Mustang EcoBoost with a Gasoline Direct Injection (GDI) engine. At around 100,000 miles, the engine developed severe carbon buildup, resulting in cylinder scoring and catastrophic engine failure. Despite following Ford’s recommended maintenance schedule (including a 100,000-mile GDI cleaning service performed by the dealership), my car now has one cylinder with only 70 psi compression (confirmed by borescope and mechanical test). Other cylinders measure 135–160 psi. I have learned Ford is aware of this issue and has made design changes in later models (adding extra fuel pumps/dual injection systems) to address it, but no recall or owner warning has been issued for earlier EcoBoost Mustangs. My research and discussions with BG Products and independent experts show this is a common flaw with GDI-only systems, and Ford has failed to inform owners or provide a lasting solution. The dealership and Ford have offered limited goodwill, but the engine is beyond repair and requires a full replacement. I believe Ford’s failure to warn owners about this well-known defect constitutes a safety and reliability risk. I am requesting NHTSA to investigate this widespread issue and require Ford to take responsibility for affected vehicles.

The contact owns a 2018 Ford Mustang. The contact stated that while starting the vehicle, there was a misfire coming from the engine. The contact stated that the vehicle was shaking abnormally, with the check engine warning light illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed and determined that the head gasket had failed, and the engine needed to be replaced. The vehicle was not repaired. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 66,637.

Took Mustang Ecoboost to Ford dealership as result of steady check engine light. Prior to check engine light rough idle at start up that smooths out after 10 to 15 seconds. Dealer identified CYL 3 misfire as well as random misfires. They also observed carbon tracking on plugs. Dealer replaced plugs and performed GDI cleaning service. About three weeks following repair same conditions reappeared rough idle and check engine light. Upon dealer inspection and use of bore scope discovered coolant intrusion in cylinder and recommended long block engine replacement. The second dealer appointment was several days after my warranty expired and mileage was 30,106 miles. Although the dealership was very supportive and understanding Ford would not provide any assistance even after I also pursued relief directly. As a result the long block engine replacement cost is $8,200. After considerable research was able to identify that ecoboost 2.3 engines as well as other small ecoboost engines all had a block defect that has since been corrected. The defect tends to permit, over time, coolant to leak into cylinders. Although a new head gasket may correct the condition, Ford normally recommends long block engine replacement as a long term fix. This condition if not attended to or if coming on suddenly will cause total engine failure. And, as failure can only occur when operating an engine failure under any driving condition is fraught with danger. To my knowledge Ford has not taken any steps to address this issue with the 2.3 liter engine built prior to about February 2020. And, at that time made an engineering change to the engine block addressing the design defect. Additionally, Ford did provide relief to owners of other smaller ecoboost engines having a similar design defect. At the present time there are several class actions suits pending for this 2.3 coolant intrusion issue. One final point should an ecoboost experience CYL or random misfires ensure bore scope is employed.