Quality improvements include: - Optimizes cabin ventilation strategy at high speeds
full bulletin at NHTSA ↗2021 Ford Bronco engine problems
moderate Owners of the 2021 Ford Bronco have filed 60 NHTSA complaints about the engine at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Complaints
60
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2021 Bronco (this page) | 60 |
| 2022 Bronco | 22 |
| 2023 Bronco | 14 |
1crash
When does it fail?
Of the 60 engine complaints filed for the 2021 Ford Bronco, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Owners have filed 60 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
Engine accounts for 28% of all owner complaints filed against this vehicle, across 10 categories tracked.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
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)
full bulletin at NHTSA ↗Some 2021-2025 Bronco and 2024-2025 Ranger vehicles equipped with a 2.7L/3.0L EcoBoost engine may require removal of the engine front cover due to various concerns. Workshop Manual, Section 303-01 has been updated with improved engine front cover removal and installation service procedure steps including a new body removal and install step.
full bulletin at NHTSA ↗Some 2021-2024 Edge/Nautilus, 2021-2025 Bronco/Bronco Sport/E-Series/Escape/Corsair/Expedition/Navigator/Explorer/Aviator/F-150/F-Super Duty/Mustang/Ranger, and 2022-2025 Maverick vehicles may require an A/C compressor clutch assembly replacement be performed for various concerns. Workshop Manual (WSM), Section 412-00 Removal and Installation has been updated to eliminate the need to remove and install the A/C compressor to change out the A/C Compressor clutch assembly.
full bulletin at NHTSA ↗Some 2020 Continental, 2020-2024 Edge/Nautilus, 2020-2025 Explorer/Aviator/Escape/Corsair/F-150/F-Super Duty/Ranger/Transit/E-Series, 2021-2025 Bronco, and 2022-2025 Maverick vehicles may require an engine cooling system flush to be performed for various concerns. Workshop Manual (WSM), Section 303-03 has been updated to eliminate the need to remove and install the radiator assembly to perform a radiator flush.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Engine failures in 2021 Broncos center on cracked or broken intake valves, a defect Ford recalled under 24S55 for 2.7L and 3.0L engines but left with no remedy. Owners report the valve issue stems from hardness defects in parts made at Ford's Lima facility. Valve failures typically happen under 7,000 miles, sometimes as low as 625 miles. The engine loses compression, power cuts out while driving at highway speed with no warning, and the vehicle won't restart. One owner's wife nearly crashed with their daughter when the engine died on a gas station entrance. Another was stranded 24 miles from a maintained road in 100-degree heat. Several found dealers misdiagnosed the valve crack, either recommending full engine swap when a cylinder head replacement could work, or missing the valve defect entirely even when owners asked about the recall.
Beyond valve failures, owners report fuel pump faults causing sudden stalls during highway driving, with parts backordered for weeks. A smaller cluster describes intermittent low fuel pressure events that dealerships cannot replicate or explain—possibly tied to an ongoing NHTSA investigation. One muffler showed corrosion and perforation with no impact damage, and one owner's engine developed a rough idle at purchase that no diagnostic code captured.
Complete engine replacement is the standard fix for valve failures, though some independent shops can repair the cylinder head for less money and faster turnaround. Warranty coverage depends strictly on mileage at failure, leaving out-of-warranty owners to fight Ford for coverage despite recalls issued before the warranty expired.
Same Ford Bronco engine reports on nearby years: 2022 · 2023
Failure modes owners describe
Intake valve cracking and breakage
Intake valves crack or break under load, causing compression loss, power loss, and catastrophic engine failure. Ford's recall 24S55 identified this defect as originating from hardness issues in valve material from the Lima manufacturing facility. Valves may drop into cylinders, punch holes in the engine block, or fragment internally.
When: Early ownership, typically under 7,000 miles, though timing varies. One owner reported failure at 625 miles; others at 6,800+ miles.
Symptoms owners cite: Check engine light (sometimes delayed or absent until stall); Loss of power while driving; Engine rough idle or sputtering before failure; Engine shuddering or bucking; Engine stalling without warning; Inability to restart; Ticking or clicking sounds from engine; Grinding sounds from engine; White smoke or large amounts of smoke from engine/tailpipe; Smell of smoke or unusual odors; Metal or debris found in oil; Reduced fuel pressure (DTC)
Codes mentioned: Low compression in cylinders, Dropped or broken intake valve, Metal in oil, Low fuel pressure DTC (in some cases), Catastrophic engine failure
Repairs/costs cited: Complete engine replacement required. Owners report costs of approximately $13,000 for full replacement. Some dealerships recommend only cylinder head replacement with new valves at lower cost. Repair times range from 1 month to several months depending on parts availability. One owner's second opinion mechanic suggested head replacement could resolve the issue at half the dealership cost.
Recalls/TSBs owners mention: Ford Recall 24S55 issued for 2.7L and 3.0L engines; insufficient response for 2.3L engines. Recall 24S55 states no remedy initially available. Vehicles within warranty period covered by Ford warranty; owners exceeding warranty mileage (per manufacturer's strict interpretation) denied coverage even though recall was issued before warranty expiration. Some owners report dealerships failed to connect valve issues to recalled defects or inform owners of pending recalls.
Fuel pump failure
Fuel pump or fuel module inside the fuel tank malfunctions, causing loss of fuel pressure and sudden engine stall during highway driving. Some cases involve low fuel pressure DTCs being recorded.
When: Various mileages reported: 625 miles, 16,900 miles; timing uncertain in some cases.
Symptoms owners cite: Loss of motive power while driving; Inability to accelerate; Engine stall without warning; Inability to restart vehicle; Engine light illumination (sometimes)
Codes mentioned: Low fuel pressure DTC, Fuel pump failure, Fuel module failure
Repairs/costs cited: Engine replacement initially misdiagnosed in some cases before fuel system diagnosis. Parts unavailable; one owner waited over 10 days at dealership awaiting fuel pump parts. No cost estimates provided by owners.
Recalls/TSBs owners mention: Manufacturer determined some vehicles were not under recall for fuel system failures. Owners advised to contact NHTSA. Recall 25V455000 (Fuel System, Gasoline) noted in one case with parts not yet available.
Spark plug failure / piston contact
Spark plugs shear off or become mashed/crushed by pistons, often associated with valve failures or catastrophic internal engine damage. In some cases, the spark plug diode breaks off from internal contact rather than external impact.
When: Concurrent with or secondary to intake valve failure or engine failure event.
Symptoms owners cite: Sheared or mashed spark plugs on one or more cylinders; Metal debris in cylinders and intake manifold; Complete engine failure requiring replacement
Codes mentioned: Sheared spark plug, Metal debris in engine, Catastrophic engine failure
Repairs/costs cited: Complete engine replacement required. No independent repair possible for spark plug damage alone when associated with internal engine failure.
Engine misfiring and power loss (unresolved fuel pressure events)
Intermittent episodes of unexplained low fuel pressure, engine stalling, and inability to restart that resolve spontaneously after hours of waiting. Dealerships cannot replicate or definitively diagnose the cause. Possibly related to NHTSA investigation PE24019.
When: Multiple incidents reported; one owner experienced three separate stall events over time.
Symptoms owners cite: Sudden stall while driving and pressing accelerator; Inability to restart immediately; Vehicle restarts spontaneously after several hours; System shows low fuel pressure event but intermittent; No replicable diagnostic findings
Codes mentioned: Low fuel pressure event (recorded but not reproducible)
Repairs/costs cited: No repair completed. Multiple dealership visits unable to replicate or resolve issue. Owners report dealerships cite 'bad gas' or inability to diagnose.
Recalls/TSBs owners mention: NHTSA investigation PE24019 ongoing since July 2024. Dealerships did not proactively inform owners of investigation despite being asked about similar incidents.
Muffler corrosion / perforation
Muffler develops a hole with no impact damage, suggesting corrosion. Exhaust leaks from the hole with staining showing prolonged leakage history.
When: Timing not specified; detected during vehicle warm-up.
Symptoms owners cite: Plumes of smoke from muffler and tailpipe area; Exhaust leaking from underneath vehicle; Hole in muffler bottom with no dent or impact damage
Repairs/costs cited: No repair information provided.
Rough idle with no diagnostic code
Engine idles very rough with bouncing RPM that does not stabilize smoothly. Condition present at purchase and worsens over time. No check engine light or diagnostic code present despite obvious mechanical issue.
When: Present at 10,000 miles and worsening.
Symptoms owners cite: Very rough idle; Bouncing RPMs; Rough running gets worse with additional miles; No check engine light or codes generated
Repairs/costs cited: Owner reports intention to take to dealer; no repair status given.
Synthesized from 60 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
The contact owns a 2021 Ford Bronco. The contact stated that while driving at an undisclosed speed, she depressed the accelerator pedal however, the engine failed to engage, and the vehicle stalled. The vehicle was towed to the contacts residence. No warning lights was illuminated. The vehicle was not diagnosed or repaired. The dealer was notified, and the contact was scheduled and appointment…
Had engine trouble with your 2021 Ford Bronco?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2021 Ford Bronco?
It's a documented issue but not catastrophic. 60 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Based on the 60 complaints filed, engine issues most often appear around 7,607 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Ford/Bronco.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.