2021 Ford F-350 SD engine problems

14 owner complaints filed with NHTSA name the engine on the 2021 Ford F-350 SD — 15% of all complaints for this model year.

Engine complaints

15%

share of all complaints

—

median reported incident mileage

0 / 4

crash / fire reports

What owners report

“Cold side intercooler boost tube cracked due to constant vibration impact from coolant overflow hose routed directly above and on top of it. Part and vehicle is available for inspection. The split in the boost hose caused me to loose power while attempting to merge onto a road, almost being hit by…”
filed Feb 19, 2026
“At this point, nothing has happened. This is a fuel pump, bio-diesel issue that can cause a lack of power which is a safety risk. This recall has been active for 7 months with no remedy listed, but according to Ford Motor Company will require a software update? The remedy is replacing the fuel pump…”
filed Jul 14, 2025

Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.

This article supersedes TSB 25-2572 to update the Parts List to correct the part number LC3Z-6006-L to LC3Z-6781-A, remove the flex plate bolts AL3Z-6379-BA from the parts list as these bolts are in kit LC3Z-6781-A…
TSB 26-2256 · Service Bulletin/Repair Instructions · issued Jun 19, 2026
Some 2021-2026 F-150 vehicles equipped with a 5.0L/5.2L engine, 2021-2025 F-Super Duty/F-53 Motorhome/F59 Commercial Stripped Chassis vehicles equipped with a 6.8L/7.3L engine and 2021-2025 E-Series/F-650/F-750 vehicles…
SSM 54678 · Service Bulletin/Repair Instructions · issued Mar 20, 2026