gas in engine oil

[Bigjohn17201]

check engine light came on, running rough, problem is oxygen sensor - checked the oil level, and I smelled gas on the dipstick. What is the cause and cure

[Dave at Pelican Parts]

If way too much gas goes into the combustion chambers, it can leak past the rings into the oil. Gasoline is not a very good lubricant for the motor parts, so you should change the oil before driving it. A bad O2 sensor can make the mixture go rich, though it could also be triggering a warning because it is detecting such a huge amount of fuel.

A number of possible causes; if you don't find anything unplugged or any obvious damage it may be best to take the car to a specialist.

Note that generic code readers will not see all the possible codes; there are some that are BMW/MINI specific and you need one of their code readers to see them.

--DD