After a little more than a year, the NHTSA is closing its probe into Ford EcoBoost engine failures.
As of October 31, the National Highway Traffic Safety Administration (NHTSA) published a “closing resume” stating it is closing its investigation into Ford Motor Company over reports of certain 2021-2022 models suffering from catastrophic engine failure. The agency determined ending the probe appropriate, as Ford is currently taking action to address ongoing concerns in multiple ways with the formal recall it launched on August 23, 2024. As these sorts of investigations aim to determine whether a recall is needed, the investigation is no longer necessary since Ford already went ahead and took action of its own accord.
Through the investigation, we learned that Ford knew about an issue lurking within its 2.7-liter and 3.0-liter ‘Nano’ family of EcoBoost engines since 2021. The twin-turbocharged, six-cylinder engines are used in the company’s mid-size vehicles including the Bronco, Explorer, F-150 and the now-defunct Edge, as well as the Lincoln Aviator and Nautilus. Specifically, it discovered that intake valve fractures were happening at relatively low mileages — under 20,000 miles — and impacted valves were dropping into the cylinder and contacting the piston, causing catastrophic engine failure.
What caused the problem?
More than 60 documents published through the NHTSA’s recall website document the thirteen-month investigation, including the agency’s Office of Defects Investigation (ODI) visiting Ford facilities to review technical information related to Nano engine valve failures. In coordination with the NHTSA’s own testing facilities, both parties analyzed field data to determine the root of the problem.
According to the published report, “Forensic analysis of fractured intake valves demonstrated that defective components exhibited ‘grinding burn’ or out of specification of hardness in the area of the keeper grooves. The presence of grinding burn is evidence that during the groove grinding phase of production, the temperature of the valve became sufficiently high to alter the microstructure of the material and is indicative that the valve supplier’s manufacturing processes were not within control specifications. Grinding burn results in a hard, brittle microstructure and high residual stresses toward the surface of the valve. Through normal engine loading, a valve with grinding burn will likely fracture at the area of highest vulnerability, which is the third keeper groove.”
Following up to the ODI’s request for more information, Ford provided documentation of 396 customer complaints for engine failure caused by defective intake valves. It also processed 825 warranty claims and replaced 936 engines. Taking into account the ODI’s own data with manufacturer failure reports, there were 1,066 failures within the population of 411,315 vehicles under investigation. That amounts to a failure rate of roughly 0.26%. (The ODI documentation shows 1,761 total reports, but the 1,066 figure eliminates duplicate reports sent by Ford Motor Company).
How is Ford addressing the issue?
On August 23, 2024, Ford launched a recall (designated 24V-635 by the NHTSA) to address engine failures between the 2021-2022 model years. In total, that recall covered 90,736 vehicles built between May 1, 2021 and October 31, 2021, give or take a few days depending on the vehicle. The recall population includes vehicles that were most prone to failure, built within the period Ford’s analysis determined the faulty valves were installed in 2.7-liter and 3.0-liter EcoBoost engines.
Ford’s solution to the problem included a dealer inspection. Once an owner brought their car to the dealership, technicians would an “accumulation procedure” if the engine hadn’t yet hit the automaker’s pre-determined failure point. Earlier reports determined nearly half of all engine failures took place before the vehicles reached 5,000 miles, while the “vast majority” of failures occurred before 20,000 miles.
The dealer procedure involved a high RPM engine cycle, which aimed to determine whether a specific engine had faulty intake valves. If it failed the accumulation test (blew up, in less jargon-heavy terms), the dealer would replace the engine under warranty.
In addition to the recall itself, Ford launched a separate “customer satisfaction campaign” (24N12), which extended the warranties for all owners subject to the recall. Even if their vehicle passed the accumulation test, or if it received a new engine, Ford will provide extended warranty coverage of 10 years or 150,000 miles, whichever comes first.
After the so-called “spike period” between May and October 2021, valve supplier Eaton Corporation implemented improvements in their manufacturing process, including a decision to change the metal alloy used to produce the intake valves. As such, vehicles built after October 2021 — including 2022 model year vehicles through to the present day — should not have this specific issue, and by extension Nano engine vehicles won’t suffer a catastrophic failure due to the same issue that caused this raft of catastrophic failures.
