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Service bulletin 21B18

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10189753
Published by NHTSA2021-04-03
Manufacturer's number21B18
Manufacturer's date2021-03-30
NHTSA componentENGINE AND ENGINE COOLING

NHTSA's summary

Certain 2021 Model Year Explorer/Aviator All-Wheel-Drive Vehicles Equipped with 3.0L Engines Engine Assembly Replacement All of the affected vehicles, an oversized right-hand exhaust camshaft journal was installed in the engine assembly. This may result in a misfire and low compression condition. The check engine light will be illuminated

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Vehicles listed
FORD EXPLORER2021
LINCOLN AVIATOR2021

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
20244922024-08-23. Engine
24V6350002024-08-23. ENGINE AND ENGINE COOLING:ENGINE:HARD PARTS INTERNAL/MECHANICAL
24V5980002024-08-09. ENGINE
20214392021-07-16. Engine
20V7880002020-12-17. ENGINE

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
SSM 552282026-10-12. Service bulletin. Some 2020-2026 Aviator/Explorer/F-150/Bronco/Ranger vehicles equipped with a 2.7L or 3.0L (non-diesel) engine may need the front engine cover removed and reinstalled for various reasons. The Workshop Manual (WSM), Section 303-01 Engine > Removal and Installation > Engine Front Cover service procedure has been updated to include a new essential special service tool (ESST) guide pin alignment tool (303-1790) that is used to align the engine front cover to the engine block, preventing the O-ring seal on the engine oil galley feed tube from getting damaged during installation.
SSM 552172026-10-06. Service bulletin. Some 2020-2024 Explorer/Aviator vehicles equipped with 3.0L EcoBoost/hybrid engine may exhibit blue or black exhaust smoke on startup for the first 5 minutes after an overnight cold soak with no illuminated malfunction indicator lamp (MIL) or powertrain diagnostic trouble codes (DTCs) present. This may be due to engine oil breaching the dynamic oil seals separating the bearing core from the turbine housing in the left side turbocharger assembly. There is a new, updated left side turbocharger oil supply tube equipped with an internal check valve to prevent the engine oil from entering turbine housing after the engine is off. Replace the existing left side turbocharger oil supply tube with the updated service part that includes the check valve (service part# L1MZ-9T516-B) or latest level part. Refer to the Workshop Manual (WSM), Section 303-04 Fuel Charging and Controls - Turbocharger > Removal and Installation > Turbocharger Oil Supply Tube LH. For claiming, use causal part 9T516 and labor operation code 9440AL.
25B512026-06-05. Other. Certain 2021-2024 Model Year Bronco, 2021-2024 Model Year Bronco Sport, 2020-2022 Model Year Corsair and Escape, 2016-2024 Model Year Explorer, 2019-2020 Model Year Fusion, 2016-2018 Model Year Focus RS, 2022-2024 Model Year Maverick, 2016-2019 Model Year MKC and 2019-2024 Model Year Ranger Vehicles Equipped with a 2.0L or 2.3L Engine and Engine Block Heater System Block Heater Replacement
SSM 547952026-05-08. Service bulletin. Some 2021-2023 F-150 vehicles equipped with a 3.5L PowerBoost engine and 2020-2026 Explorer vehicles equipped with a 3.3L hybrid engine may exhibit an illuminated powertrain malfunction (wrench) indicator with diagnostic trouble code (DTC) P0A1E stored in the powertrain control module (PCM). The vehicle may be unable to enter electric-only drive modes as expected during normal drive cycles. This may be due to the software within the belt integrated starter generator (BISG). For vehicles with this condition, follow Pinpoint Test I: Battery Isolation/Voltage Stabilization Control Circuit Carry Outance located in the Workshop Manual (WSM), Section 303-06D and repair the vehicle as necessary. Note that the BISG is on backorder status at the time of this publication and Ford is working to make parts available. Engineering is investigating this concern. Monitor PTS for updates.
SSM 547562026-04-21. Service bulletin. 2021-2026 Explorer vehicles equipped with the 2.3L EcoBoost engine may require air conditioning (A/C) compressor belt removal for various reasons. The Workshop Manual (WSM), Section 303-05A Accessory Drive - 2.3L EcoBoost > Removal and Installation > Air Conditioning (A/C) Compressor Belt procedure has been revised to eliminate cutting the A/C compressor belt to remove it. Refer to the updated procedure to reuse the belt.
24N12 S22026-04-07. Other. Certain 2021 - 2022 Model Year Various Vehicles Engine Valve Inspection Test This submission includes : Technical Instructions Updated wording and description with additional photo.
SSM 542752025-10-14. Service bulletin. Some 2021-2023 Explorer vehicles equipped with a 3.0L EcoBoost engine, 2021-2023 Aviator vehicles equipped with a 3.0L EcoBoost or 3.0L plug-in hybrid electric vehicle (PHEV) engine, 2021-2023 Edge/Nautilus vehicles equipped with a 2.7L EcoBoost, 2021-2024 F-150 vehicles equipped with a 2.7L EcoBoost, and 2021-2024 Bronco and 2024 Ranger vehicles equipped with a 2.7L or 3.0L EcoBoost engine may exhibit a ticking/tapping or rattle type noise from the top front cover area of the engine. This noise may occur on initial start-up after a cold soak of 6 hours or more that may last for 2-5 seconds. This may be due to an internal component of the variable cam timing (VCT) unit. Workshop Manual (WSM), Section 303-00 > Diagnosis and Testing > Engine > Pinpoint Test F has been updated to include additional steps along with a video to identify the affected VCT unit that requires replacement.
24N12 -S12025-09-02. Other. NEW VEHICLE DEMONSTRATION / DELIVERY HOLD Safety Recall 24S55 – Supplement #1 Dated: August 15, 2025 Customer Satisfaction Program 24N12 Dated June 19, 2025 New! REASON FOR THIS SUPPLEMENT • Rental Vehicles: Added specification that long block replacement must be approved by SSSC for rental coverage to apply. • Labor Allowances: Added labor operation for photo submission on all vehicles and labor operation for borescope inspection. • SSSC Approval: Borescope photo submission required for long block approval. • Parts Handling Allowance: Added additional allowance claiming information for engine replacement. • Attachments: Technical Instructions have been added to the program. PROGRAM TERMS This program provides a no-cost, one-time repair (if needed) for an engine long block replacement for vehicles that completed the 24S55 inspection process. This program will be in effect for 10 years of service or 150,000 miles from the warranty start date of the vehicle, whichever occurs first. This is
24N10 S12025-08-01. Other. Certain 2020-2022 Model Year Explorer Police Interceptor Utility (PIU) Vehicles Engine Block Breaches This program provides a no-cost, one-time repair (if needed) to the engine long-block for 10 years of service or 150,000 miles from the warranty start date of the vehicle, whichever occurs first.
24N122025-07-02. Other. Certain 2021 - 2022 Model Year Various Vehicles Engine Valve Inspection Test