Service Bulletin - Oil leak at timing chain tensioner inspection cover due to possible insufficient sealant adhesion on inspection cover.
full bulletin at NHTSA ↗2018 Honda Accord engine problems
moderate Owners of the 2018 Honda Accord have filed 350 NHTSA complaints about the engine, typically surfacing around 73,000 miles 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 →
Failure mileage
Complaints
350
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2014 Accord | 90 |
| 2015 Accord | 45 |
| 2016 Accord | 21 |
| 2017 Accord | 34 |
| 2018 Accord (this page) | 350 |
| 2019 Accord | 86 |
| 2020 Accord | 41 |
| 2021 Accord | 18 |
| 2022 Accord | 18 |
3crashes
2fires
1injury
When does it fail?
Of the 350 engine complaints filed for the 2018 Honda Accord, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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
Of the 18 model years of Honda Accord we track for engine problems, this one carries the most owner complaints on file — 350.
Owners have filed 350 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.
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.
Service Bulletin - During engine start in cold conditions, a miscalculation in the PCM causes the air-fuel ratio to exceed DTC rich criteria, resulting in the vehicle experiencing drivability concerns. This issue is most common in regions with cold weather.
full bulletin at NHTSA ↗Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018-2022 Accords with customer complaint of Charging System Problem (battery icon) or Auto Engine Idle Stop Problem Lamp coming on the Multi-Information Display (MID). To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018-2022 Accords with customer complaint of Charging System Problem (battery icon) or Auto Engine Idle Stop Problem Lamp coming on the Multi-Information Display (MID). To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018-2022 Accords with customer complaint of Charging System Problem (battery icon) or Auto Engine Idle Stop Problem Lamp coming on the Multi-Information Display (MID). To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2018 Honda Accord 1.5L turbo has a pattern of critical engine failures that Honda's internal documentation acknowledges but refuses to cover. Owners report head gasket failure as the dominant issue—coolant leaks internally into cylinders 2 and 3 without external drips or overheating gauges climbing. This happens as early as 42,000 miles and as late as 146,000. The first sign is usually misfires and a flashing check engine light; then the car enters limp mode (dropping from 65 mph to 20 mph) with all dash warnings illuminating at once. Several owners narrowly avoided rear-end collisions from semi trucks when this occurred on busy highways.
The root cause traces back to oil dilution: fuel contaminates the crankcase, fouling injectors and spark plugs. Then coolant seeps past the head gasket, mixing with oil and fouling spark plugs further. A fuel pump recall issued in December 2023 remains unfulfilled—dealerships say parts are backordered through late 2024 and beyond. One owner used fuel pump cleaner weekly for a year waiting for a replacement part.
Repairs exceed $5,000 routine; one owner was quoted $11,000 for head replacement, fuel injectors, plugs, coils, and new head gasket. Honda corporate denies goodwill coverage citing age and mileage, even on otherwise well-maintained vehicles. Multiple owners reference the active class-action lawsuit (Bissell v. American Honda Motor Co., Case 3:24-cv-02286) and TSB MC-10234626-0001, both documenting this defect. One service manager confirmed his dealership receives three to four of these failures daily.
Same Honda Accord engine reports on nearby years: 2015 · 2016 · 2017 · 2019 · 2020
Failure modes owners describe
Oil dilution and fuel injector contamination
Gasoline contaminating engine oil, causing fuel injector fouling and repeated failures. Owners report the 1.5L turbo is prone to fuel diluting the oil, leading to clogged injectors, misfires, and multiple replacements.
When: Appears between 35,000 and 80,000 miles; one complaint at 54,084 miles
Symptoms owners cite: Loss of acceleration; Check engine light; Misfires in multiple cylinders; Oil smell like gasoline; Low oil level
Codes mentioned: P0300, P0301, P0302, P0303, P0304
Repairs/costs cited: 4 fuel injectors + related parts $1,495.53; repeated injector replacements; some shops replace injectors at $1,600
Recalls/TSBs owners mention: TSB 19-091 documents the oil dilution defect; Honda denies goodwill coverage in most cases; class-action lawsuit 1:22-cv-02662 (N.D. Illinois)
Premature head gasket failure with coolant intrusion
Cylinder head gasket fails prematurely, allowing coolant to leak internally into cylinders and oil. This occurs without external coolant leaks, no overheating warnings, and at relatively low mileage. Affects cylinders 2 and 3 most frequently. Owners report this as a known design or manufacturing defect in the 1.5L turbo engine.
When: Between 42,000 and 146,600 miles; most common between 78,000 and 120,000 miles
Symptoms owners cite: Misfires in cylinders 2 and/or 3; Rough idle and shuddering on acceleration; Sudden loss of power, especially at highway speeds; Limp mode activation; Multiple warning lights ('Christmas tree' dashboard); Coolant loss with no external leaks; White/smoke-like exhaust; Engine overheating at idle or low speeds; Hesitation and jerking during acceleration; Blinking check engine light
Codes mentioned: P0302, P0303, P0087, P0299
Repairs/costs cited: Head gasket replacement $3,758 to $11,000 (quoted); spark plug replacement often included; timing chain, cylinder head, and fuel injector replacement sometimes required; repairs delayed due to parts backorder
Recalls/TSBs owners mention: TSB MC-10234626-0001 exists; class-action lawsuit Bissell v. American Honda Motor Co. (Case No. 3:24-cv-02286, N.D. California); Honda denies goodwill coverage on most claims, citing vehicle age/mileage; some owners report Honda corporate refused escalation and goodwill assistance
Fuel pump failure and turbocharger damage
Mechanical fuel pump seizes or fails, preventing adequate fuel pressure to the engine. Some owners also report turbo assembly and wastegate actuator wear from compensating for fuel system issues. Fuel pump recall issued but parts unavailable for extended periods.
When: One report at 78,000 miles; fuel pump recall issued 12/19/23 with widespread parts shortage through late 2024
Symptoms owners cite: Engine stall or failure to start; Limp mode; Loss of power while accelerating; Loud noise during acceleration; Whirring and smoking when accelerating; Multiple warning lights; Difficulty maintaining highway speed
Repairs/costs cited: Fuel pump replacement (mechanical Part# 16790-5PC-H02); turbo assembly replacement $6,500+; wastegate actuator or full turbo replacement; parts on backorder for months; one owner used fuel pump cleaner weekly as temporary measure
Recalls/TSBs owners mention: Recall issued 12/19/23; Honda dealerships experienced extended parts shortages (months to over a year); owners advised to use fuel pump cleaner; one owner reported dealer-to-dealer transfer of vehicle due to lack of repair progress
Spark plug failure and coil pack issues
Spark plugs foul and fail repeatedly, often stuck or seized in cylinder heads. Coil packs may also fail. Issues traced to oil dilution, coolant intrusion, or carbon buildup from misfires. Spark plug replacement is recurring and sometimes combined with fuel injector and head gasket repairs.
When: Recurring throughout vehicle life; replacements every 6 months reported in one case
Symptoms owners cite: Misfires; Rough idle; Difficulty starting; Check engine light; Power loss
Codes mentioned: P0300, P0301, P0302, P0303, P0304
Repairs/costs cited: Spark plug replacement $35–$100+ per set; may require special tools to remove seized plugs; some owners report pulling plugs with impact tools at 1,200–2,000 ft-lbs; coil pack swaps performed but often ineffective if underlying head gasket issue present
Recalls/TSBs owners mention: Service technicians acknowledge this as a common issue on 1.5T engines; fuel injectors carry a 150,000-mile/10-year warranty in some cases but not all VINs are included
VTEC solenoid and turbocharger component failures
VTEC solenoid, spool valve, turbo assembly, and turbo sensor failures occur, often secondary to primary head gasket or fuel system defects. Turbo wastegate bushings wear prematurely from poorly engineered components.
When: Timing varies; one case at 108,584 miles
Symptoms owners cite: Loss of acceleration; Check engine light; Turbo underboost
Codes mentioned: P0299
Repairs/costs cited: VTEC solenoid replacement; turbo assembly replacement (full assembly required); spool valve replacement; wastegate actuator arm bushings cannot be replaced separately, requiring full turbo replacement
Multiple warning light activation and limp mode
Dashboard displays 'Christmas tree' of warning lights (brake, emission, steering, stability, hill start, adaptive cruise, collision mitigation, road departure mitigation, tire pressure). Limp mode restricts acceleration to 20–35 mph. Often triggered by misfires or oil dilution but affects critical safety systems, disabling adaptive cruise and driver-assist features.
When: Occurs during misfire events; intermittent to persistent
Symptoms owners cite: Multiple simultaneous dashboard warnings; Loss of power to 20–35 mph (limp mode); Steering assist reduced or disabled; Adaptive cruise control disabled; Brake system warnings; Vehicle stability assist warnings; Road departure mitigation disabled
Codes mentioned: P0300, P0302, P0303
Repairs/costs cited: Diagnostics often clear after vehicle restart; recurring without underlying fuel injector/head gasket repair; some repairs covered under warranty after inspection
Engine fire
One documented case of engine catching fire on highway while vehicle running at 65 mph for 15 minutes. Vehicle continued moving even after foot and parking brakes applied. Fire department responded and totaled vehicle.
When: 16 months of ownership; highway driving at 65 mph
Symptoms owners cite: Burning smell; Smoke from engine bay; Brake failure (both foot and parking brake ineffective)
Repairs/costs cited: Vehicle totaled
Synthesized from 350 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 4 most recent
Car would shake in the morning would wait till warmed. Immediately brought to Honda where I had a diagnostic completed approx. 9/3. Reports says head gasket. Car well taking care (maintenance) no reason for blown head gasket. Got a second opinion They had the car for a week. No warning lights, and did another diagnostic and nothing showed at the time. Brought the car home. After a few months…
Hi, to whom it may concern my dashboard lights have been on for months now and I’ve taken it to the dealership I purchased my car from and it comes back that it’s the turbo that needs replacing. The pricing of that is ridiculous and I’m currently not the ONLY one with this issue ! It’s an ALL AROUND THE WORLD thing! I’m not sure about anybody else but I don’t have that type of money plus while…
Fuel pump is bad causing the car not to start.
The contact owns a 2018 Honda Accord. The contact stated that the backup camera was turning on and off. While reversing, the backup camera turned black over time. The check engine and ACC adaptive cruise control warning lights were illuminated. The vehicle was taken to the local dealer, who confirmed the vehicle was not covered under NHTSA Campaign Number: 18V629000 (Back Over Prevention,…
Had engine trouble with your 2018 Honda Accord?
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 2018 Honda Accord?
It's a documented issue but not catastrophic. 350 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?
Across the 56 complaints that reported odometer mileage, most engine failures cluster between 33,787 and 100,000 miles, with the median around 73,000. A quarter of owners report trouble before 33,787; a quarter make it past 100,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
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/2018/Honda/Accord.
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.