2021 Lincoln Nautilus

On July 22, 2022, the Office of Defects Investigation (ODI) granted a Defect Petition (DP22001) and opened a Preliminary Evaluation (PE22007) to investigate allegations of loss of motive power in model year (MY) 2021 Ford Bronco vehicles equipped with 2.7L EcoBoost engines. Complainants were reporting sudden engine failure while driving resulting in a loss of motive power, often without the ability to restart. During PE22007, the cause of engine failure and loss of motive power in the subject vehicles was determined to be intake valve fracture, and the full scope of vehicles affected by the subject defect was identified as all MY 2021-2022 Ford and Lincoln models equipped with either the 2.7L or 3.0L EcoBoost engines, referred to as the “Nano” engine family.  If an intake valve fractures in the subject engines, it may drop into the cylinder and contact the piston, often resulting in catastrophic engine damage. On September 29, 2023, PE22007 was upgraded to an Engineering Analysis (EA23002) to further investigate the subject defect across the full scope of affected vehicles. During EA23002, ODI visited Ford facilities to review technical information related to intake valve fracture in “Nano” engines, coordinated with NHTSA’s Vehicle Research and Testing Center (VRTC), and analyzed updated field data relating the subject defect. Forensic analysis of fractured intake valves demonstrated that the defective components exhibited “grinding burn” or out of specification 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. In its response to the EA23002 Information Request (IR) letter, Ford provided evidence of 396 customer complaints (including field reports), 825 warranty claims, and 936 engine exchanges. When considering both ODI and manufacturer failure report data, there have been reports representing 1066 unique vehicles within the subject vehicle population. Analysis of the failure report data demonstrates that vehicles equipped with potentially defective intake valves were built within a production “spike period” of May 2021 – October 2021. The beginning of the spike period corresponds to a ramp up in production at the valve supplier manufacturing facility, and the end of the spike period aligns with the implementation of several mid-production process improvements and the decision to change the metal alloy used to produce intake valves from “Silchrome Lite” to “Silchrome 1”. Ford began investigating the subject defect in July 2021, determined the root cause, and took corrective measures for the new production vehicles. Analysis of the failure report data demonstrates that these corrective actions were successful in eliminating the risk of intake valve fracture for subject vehicles produced after October 2021. However, Ford did not take any field action to address vehicles produced during the spike period, and in the several months following the implementation of the production changes, a significant number of field failures continued to occur. It is Ford’s assessment that not all valves produced during the spike period are defective, and that failures associated with the subject defect occur at low time in service. Analysis of the failure report data demonstrates that the vast majority of failures have occurred before 20,000 miles with over half of all reported failures occurring before 5,000 miles. The rate of reported failures related to the subject defect has steadily decreased since November 2021. ODI coordinated with NHTSA’s National Center for Statistics and Analysis (NCSA) to conduct statistical analysis and predict the number of future failures associated with the subject defect. The results of this analysis, and the trends identified through the failure report data are generally consistent with Ford’s assessment that defective intake valves will likely fail at a low time in service and indicate that the majority of subject vehicles equipped with defective valves have already experienced a failure. On August 23, 2024, Ford submitted recall 24V635 for subject vehicles equipped with “Nano” engines and built within the production spike period identified above (total population 90,736 vehicles). The remedy includes an inspection at a Ford/Lincoln dealership where the lifetime engine cycles of the vehicle will be determined. If a vehicle does not meet a threshold for lifetime engine cycles, the dealership will conduct a high RPM engine cycle accumulation procedure, which aims to identify if the vehicle is equipped with defective intake valves. Any vehicle that fails the accumulation procedure will receive an engine replacement under the recall. In addition to recall 24V635, Ford has stated that it will launch customer satisfaction campaign 24N12, which will provide extended warranty coverage to the subject vehicles through the earlier of 10 years or 150,000 miles. In view of the recall action being taken by Ford, ODI is closing this Engineering Analysis. To review the reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

"The spot welds and inner sheet metal at the driver door check arm attachment point have structurally failed and cracked. This prevents the door from operating safely and creates an imminent risk of the door failing to latch or inadvertently opening while driving, matching the failure mechanism in NHTSA Investigation PE 23-013.

NHTSA ID

11776406

Incident

Oct 19, 2026

Drivers front door inner sheet metal structure has failed/torn at the check arm mounting points under normal operating conditions.. safety hazard. Dealership and Lincoln will not take full responsibility after known structural defect exists. I note on your website that in Nautilus alone there are 10 complaints including mine. Our car had less than 42,000 miles when we noticed. The entire door needs to be replaced.

NHTSA ID

11772775

Incident

Aug 1, 2026

Drivers front door inner sheet metal structure has failed/torn at the hinge and check arm mounting points under normal operating conditions.. safety hazard. Dealership and Lincoln will not take full responsibility after known structural defect exists

NHTSA ID

11771453

Incident

Oct 15, 2026

Both front doors on my 2021 Nautilus Reserve have structural stress cracks in the sheet metal surrounding the check-arm bracket, along the edge of the recessed mount and under the weatherstrip. I first noticed cracking and popping when opening and closing the doors on 8/1/2026 at about 84,000 miles. No collision; normal use. The bracket mounts to the inner door panel with no reinforcement. The panel visibly flexes every time the door opens and checks, and that flexing has fatigued and cracked the metal. The cracks are growing. This is a safety issue. Once the bracket tears out, the door has no hold-open or stop. It can be pulled open by wind, strike a person or vehicle beside it, or swing closed on an occupant's arms or legs. Complaint 11767021 reports a 2021 Nautilus door torn from the owner's hand by wind after the check broke. In PE23-013, NHTSA's investigation of the same failure on the Ford Escape, NHTSA documented 25 injuries, mostly from doors closing on occupants, and cited risk of a door failing to latch, failing to open, or opening while driving. Both my front doors are affected, so the driver and passenger exits are both at risk. At least eight other 2021 Nautilus owners have filed NHTSA complaints on the same failure, and Ford Edge owners report it too. Ford covers this failure on the 2020-2023 Escape under CSP 23B56 (reinforcement plate or new door, no cost, no mileage limit), but no recall or program covers the Nautilus or Edge. Lincoln (case CXH-09573152) offered $4,400 goodwill instead of a full repair. Other 2021 Nautilus owners report this failure as early as 20,000 miles, so it is a design flaw, not wear. Re-welding or installing the same unreinforced door will not fix it; any remedy must add reinforcement at the check-arm mount. I request an investigation of front door check-arm related stress cracking on doors of 2019-2023 Nautilus and Edge vehicles. Photos, video, and an evidence brief are available.

NHTSA ID

11770905

Incident

Oct 1, 2026

Transmission was shuddering when it shifted gears. It would lose power and jerk between each gear. We paid for diagnostic at the dealership and they diagnosed as torque converter shudder under 2 separate TSB's. Dealership offered to fix at a cost of $6400. Told not to drive the vehicle or at least as little as possible. They refused to cover this under the TSBs. Contacted Lincoln Client Care. The shudder became worse even driving through town and it would jerk and the RPMS were jumping all over. Also took it to AAMCO after dealership stated they would not cover it under a TSB. AAMCO provided free diagnostic and came to the same conclusion of the torque converter and estimated cost of $3300, which was 3100 less than dealership. Asked Lincoln for goodwill fix and they spent a month talking to the dealership trying to get the dealership to a lower price, to whichthe dealership raised the price to $6800 and they offered 4k in goodwill, but said that it would take 4 to 6 weeks to get the parts. By this time AAMCO already had the parts after waiting3 weeks on backorder and AAMCO made te fix at an out of pocket cost of $3300. Total out of pocket costs were the 300 for the diagnostic and the 3300 for the torque converter fix.

NHTSA ID

11768750

Incident

Jun 1, 2026

Noticed cracking sound when opening and closing front drivers door. Subsequently discovered same issue on Ford Edge (recall in place) and many other owners having same problem (FaceBook posts).

NHTSA ID

11767920

Incident

Sep 16, 2026

Door check is broken in high winds the door pulled out my hand. Could have injured someone of that person was standing near the opening path of the door.

NHTSA ID

11767021

Incident

Sep 18, 2026

The driver's side door is cracked at the door hinge assembly. This is a widely documented defect. My door cracked at 50,000 miles. There are thousands of 2019-2024 Nautilus's with this defect. Lincoln wants $5,000 to replace the door. They offered $2,000 toward the repair. This should be a recall.

NHTSA ID

11760735

Incident

Apr 1, 2026

This bulletin supersedes 26-2171. Reasons for update: update the Parts list to add a note to clarify the application of the part numbers W520102-S442 and 4S4Z-3N324-AA "FWD Only". Some of the vehicles listed in the Model statement above may exhibit all of the following conditions:  Shudder condition, most noticeable at speeds below 60 mph (100 km/h)  No relevant diagnostic trouble codes (DTC) present  Traceable shudder event with IDS/FDRS reading *(Figure 1)* This condition may be perceived/felt as an engine misfire. This may be due to a concern with the output planetary assembly.

This bulletin supersedes 26-2297. Reason for update: Add 2022-2025 Transit vehicles. Some of the vehicles listed in the model statement above equipped with SYNC4 may experience a blank center display screen or black center display screen after welcome animation. The rear-view camera will still function when shifting the vehicle to reverse under these conditions.

This article supersedes TSB 25-2466 to add Bronco Sport, Escape, Maverick and Corsair, as well as removing Expedition and Navigator. One time use parts for Corsair and Bronco Sport were also added to the parts list. Some of the vehicles listed in the Model statement above may exhibit a headliner rattle or sagging condition around the roof opening panel. This may be due to the adhesive separating from the headliner substrate.

This bulletin supersedes 26-2171. Reasons for update: update the Parts list to add a note to clarify the application of the part numbers W520102-S442 and 4S4Z-3N324-AA "FWD Only". Some of the vehicles listed in the Model statement above may exhibit all of the following conditions:  Shudder condition, most noticeable at speeds below 60 mph (100 km/h)  No relevant diagnostic trouble codes (DTC) present  Traceable shudder event with IDS/FDRS reading *(Figure 1)* This condition may be perceived/felt as an engine misfire. This may be due to a concern with the output planetary assembly.

This bulletin supersedes 26-2171. Reasons for update: update the Parts list to add a note to clarify the application of the part numbers W520102-S442 and 4S4Z-3N324-AA "FWD Only". Some of the vehicles listed in the Model statement above may exhibit all of the following conditions:  Shudder condition, most noticeable at speeds below 60 mph (100 km/h)  No relevant diagnostic trouble codes (DTC) present  Traceable shudder event with IDS/FDRS reading *(Figure 1)* This condition may be perceived/felt as an engine misfire. This may be due to a concern with the output planetary assembly.

Some 2021-2026 Ford/Lincoln vehicles may exhibit various symptoms including but not limited to the auto start/stop system not operating as intended with a "Check Charging System" message in the instrument panel cluster (IPC) while the charging system is operating properly with no charging related diagnostic trouble codes (DTC) stored. This may be due to someone using an aftermarket programmer to change the body control module (BCM) configuration to disable the auto start/stop system or perform other unsupported programming modifications. To correct this condition on F-150 and Bronco vehicles, download and run the Ford Diagnosis and Repair System (FDRS) application titled "BCM-Charging System Configuration Correction". Running this application will determine if the BCM configuration was modified by the customer and if so, provide the option to return the configuration back to factory settings. For other vehicle models exhibiting concerns related to unsupported aftermarket BCM programming, submit a Technical Support Request (TSR) requesting support to revert the BCM configuration