"I heard they are quite reliable as long as you keep it mostly stock. Every dilution issue I've seen came from short trips in cold weather."
RISKY
63/ 100
"Capable engine, oil dilution clouds everything"
190
Max HP
315
Torque Nm
7,500
Oil interval km
0
Recalls
4
Known issues
Known Issues
Oil Dilution by Fuel (Gasoline Entering Crankcase)€0–3,000 · 10,000–100,000 kmCRITICAL
A well-documented and litigated problem on MY2018–2021 examples. Gasoline enters the crankcase and mixes with engine oil, thinning it and reducing its lubrication effectiveness. Most pronounced in cold climates with frequent short-trip driving. A class-action lawsuit was filed. Honda issued software updates but many owners report the problem persists. Long-term bearing and journal wear is a real risk if not managed with frequent oil changes.
Oil level rising above the full mark on the dipstick
Strong fuel smell from the oil
Milky or unusually thin-looking oil on dipstick
Increased oil consumption in some cases after dilution cycles
DIY: Easy to detect, hard to permanently fix without usage pattern change
Direct Injection Carbon Buildup on Intake Valves€300–800 · 80,000–160,000 kmHIGH
As a direct-injection turbocharged engine, the L15B7 does not wash intake valves with fuel. Carbon deposits accumulate on the back of the intake valves over time, restricting airflow and causing rough idle, hesitation, and power loss. Walnut blasting is the standard fix.
Cam Sensor Fault and Ticking at Higher RPM€150–600 · 100,000–160,000 kmMODERATE
Reports from tuned and higher-mileage examples indicate intermittent cam sensor A fault codes appearing at 3,500–5,000 RPM, sometimes accompanied by engine ticking. More frequently observed on modified or tuned L15B7 units but also noted on stock engines. Root cause is not always straightforward and may involve the sensor, wiring, or deeper valvetrain wear.
Check engine light with cam sensor A fault code
Engine ticking noise particularly at higher RPM
Intermittent rough running at mid-to-high RPM
DIY: Moderate — sensor replacement is straightforward but diagnosing ticking requires deeper inspection
General Turbo System Wear (Boost and Gasket Stress)€200–1,500 · 120,000–200,000 kmLOW
Community sources note that sustained boost pressure puts stress on turbo gaskets and related seals over time. Proper oil change intervals are critical to turbo longevity given the oil dilution risk. No widespread catastrophic turbo failures reported on stock, well-maintained engines.
Pull the dipstick and check for elevated oil level above the full mark — a sign of fuel dilution
Smell the oil on the dipstick directly; a strong petrol odour confirms active dilution
Request full service history and verify oil changes were performed every 7,500 km or less
Ask specifically whether Honda's oil dilution software update or TSB was applied — confirm with dealer records
During test drive, accelerate through 3,500–5,000 RPM and listen carefully for any ticking or cam sensor-related hesitation
Use a borescope or request a borescope inspection of the intake valves to assess carbon deposit severity before purchase
Service Reality
Community oil interval7,500 km
Oil specificationHonda Genuine 0W-20 Full Synthetic or equivalent meeting Honda HTO-06 specification
Est. ownership cost (2yr)€800–2,000 over 5 years for proactive maintenance including frequent oil changes and one walnut blasting service; costs can exceed €3,000 if dilution damage goes undetected and causes bearing wear
The Honda L15B7 is a genuinely capable and punchy engine let down significantly by a well-documented oil dilution problem that has resulted in a class-action lawsuit. If you live in a cold climate and do frequent short trips, this engine is a poor match for your use case. Buyers who primarily highway-drive in temperate climates and commit to 7,500 km oil change intervals report far fewer problems. Always verify the oil dilution software update has been applied and treat the dipstick check as a monthly routine — this single habit will determine whether your ownership experience is trouble-free or expensive.
Parts People Buy
Honda Genuine 0W-20 Full Synthetic Engine OilLink unavailable
Oil Dipstick Fuel Dilution Test KitLink unavailable
OBD-II Bluetooth Scanner for HondaLink unavailable
Intake Valve Walnut Blasting Service KitLink unavailable