2020 Ford Mustang Engine Problems

FAILURE TO NOTIFY/ADDRESS A KNOWN ISSUE DURING THE WARRANTY PERIOD Vehicle has been serviced in accordance with Ford’s recommended maintenance schedule by Joe Cooper Ford of Edmond, Oklahoma, since purchase. At service appointment in September 2025, with 59,968 miles – just prior to the 60k mile powertrain warranty expiration – specifically requested a thorough inspection of any conditions that could potentially be addressed under warranty coverage. During that visit, Joe Cooper Ford documented that the “coolant was low (at minimum mark) and dirty” and recommended a coolant system fluid exchange. This finding occurred in the context of the well-documented coolant intrusion defect affecting 2017–2020 Ford Mustangs and other Ford models. When an authorized dealer observes conditions consistent with a known defect during the warranty period, reasonable warranty administration requires disclosure and further diagnostic evaluation, so the customer has a meaningful opportunity to pursue timely repair. By January 2026, at only 61,640 miles, were informed our engine had failed. No such disclosure or evaluation was provided. As a result, we were deprived of a reasonable opportunity to address the condition under warranty prior to expiration. The subsequent engine failure occurred after the warranty period but was directly preceded by these unresolved indicators. Under these circumstances, denial of warranty consideration is inconsistent with the purpose of the warranty and reasonable consumer expectations.

I had the coolant gasket problem that resulted in having to get the engine replaced. It was a 202 mustang ecoboost premium.

Coolant intrusion into cylinder/cylinders Problem confirmed by a dealer Check engine light, cylinder 1 missfire is when I noticed an issue

The contact owns a 2020 Ford Mustang. The contact stated while driving at an undisclosed speed, there were several unknown warning lights illuminated. Additionally, the contact noticed smoke inside the vehicle and there was smoke coming from under the hood. The vehicle was towed to the dealer where it was diagnosed with failed pistons and a blown engine. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 73,300.

On 03.29.25 (Saturday) the car started rough and the check engine light came on. I took it to the mechanic 03.31.25 (Sunday) and they inspected the car and told me that it is either the head gasket or the engine block is cracked because there is coolant intrusion into the cylinders. They asked me to call FORD customer service and ask if there was any way to cover it under warranty as the car only has 64K miles. I was told no, the warranty was 5yrs or 60K whichever came first and the 5 years was October of 2024. They suggested I file a report with the NHTSA. The vehicle right now is at the mechanic as I try to decide what I would like to do with it. If the engine failed when driving, I don't know what would have happened. There were no other symptoms to the problem prior to the failure. In fact, weeks earlier I had it inspected to see if any maintenance was needed and it got a clean bill of health.

The contact owns a 2020 Ford Mustang. The contact stated while driving 55-60 MPH, the check engine warning light illuminated. The vehicle was taken to AutoZone, where the contact was informed that there was no coolant in the vehicle. The contact added coolant to the vehicle; however, the failure persisted. The vehicle was taken to the dealer, where it was diagnosed that the head gasket had failed, causing coolant intrusion into the engine. The dealer determined that the entire long block and the head gasket needed to be replaced. Additionally, the dealer informed the contact that the long block and the head gasket needed to be aligned correctly. The vehicle was not repaired. The manufacturer was notified of the failure and offered to partially cover the cost of the repair. The failure mileage was approximately 53,500.

The contact owns a 2020 Ford Mustang. The contact stated while driving 25 MPH, the check engine warning light illuminated. The contact stated that the engine overheated while driving. The contact was able to pull over and the vehicle was towed to the local dealer to be diagnosed. The contact was informed that there was coolant in the combustion chamber, engine block, and cylinder head, and the low-pressure fuel pump had failed. The dealer recommended an engine replacement. The vehicle was not repaired. The vehicle was taken to an independent mechanic who replaced the head gasket, but the failure recurred. The manufacturer was contacted and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 86,000.

The contact owns a 2020 Ford Mustang. The contact stated that after adding oil to the engine, the contact became aware that a significant amount of the engine oil had leaked out onto the ground. The vehicle was not diagnosed or repaired by an independent mechanic or a dealer. The manufacturer was notified of the failure and informed the contact that they could not assist because the VIN was not under recall for the failure. The failure mileage was approximately 72,000.

The contact owns a 2020 Ford Mustang. The contact stated that the engine warning light was illuminated. The vehicle was taken to the local dealer, where it was diagnosed and determined that the catalytic convertor and active grill shutter assembly needed to be replaced. The vehicle was not repaired. The manufacturer was contacted and referred to the NHTSA Hotline. The failure mileage was approximately 86,000.

The contact owns a 2020 Ford Mustang. The contact stated that the engine overheated while driving at various speeds with the temperature gauge showing that the engine was hot(H). The contact stated that the vehicle hesitated while depressing the accelerator pedal with an engine misfire alert on the Ford App. The vehicle was taken to a dealer where a pressurized test was performed; the test showed no defect with the engine. The contact then took the vehicle to an independent mechanic where the spark plugs, and cabin air filter were replaced, and the fuel system was cleaned. The check engine warning light illuminated soon after the repair. The vehicle was taken back to the dealer where it remained unrepaired. The manufacturer was notified of the failure and a case was filed. The failure mileage was approximately 59,000.

The contact owns a 2020 Ford Mustang. The contact stated that while driving at 15 MPH, the check engine warning light illuminated, and the vehicle lost motive power. The vehicle was taken to a dealer where it was diagnosed that coolant had leaked into the engine, causing misfiring codes and a lack of motive power which resulted in the engine needing to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 66,500.

The contact owns a 2020 Ford Mustang. The contact stated that while driving at 15 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The check engine warning light illuminated, and the vehicle was misfiring. Additionally, the vehicle was shaking, and the contact pulled over to the shoulder of the road. The contact turned the vehicle off and restarted the vehicle. The vehicle was driven to the residence. The contact stated that the failure was persistent. The vehicle was taken to the dealer where it was diagnosed with coolant leak into the cylinders and the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and advised the contact to report the failure to the NHTSA Hotline. The failure mileage was approximately 63,000.