2016–2018 Honda Civic: Oil dilution with fuel, rising oil level (1.5T)

Symptom: The oil reads high on the dipstick and smells like gas. In cold climates you may also get misfire codes or a whirling noise.

Likely causes

1. Fuel in the oil on short trips in cold weather. Honda's fix was new engine and transmission software, plus an A/C control update that helps the engine warm up faster. Honda also extended coverage on related engine parts. The CivicX thread covers how owners got it done.
2. Long oil change intervals.
3. Too much oil added at the last service.

Cost

The software update is free. The warranty extension (camshaft, rocker arms, spark plugs) ran 6 years from the original sale date, so it has probably expired. Check your VIN anyway.

DIY or shop?

• DIY: check the oil often and change it more frequently in winter.
• Dealer: the software update.

Useful steps

1. Confirm the update shows as done on your VIN.
2. If you mostly take short winter trips, change the oil more often.
3. Report a fuel smell or oil level that keeps rising to Honda.

Vehicle focus: 2016–2018 Honda Civic.

Safety / mechanic note

Badly diluted oil can damage the engine's bearings. Get misfires or a strong fuel smell checked.