Why Does My Oil Smell Like It's Pure Petrol?

[jonD6B 0]

I have just taken off my oil filler to check whether it's blocked due to a misfire I've devloped (check my other thread) and when I smelt the small amount of oil on my fingers it smelt strongly of petrol. To the extent actually that had it not been almost black I'd have thought it was petrol! What causes this? If it's really bad news give me the diagnosis gently!

[M3Evo 0]

Might be an idea to change the oil before running the engine again

 

Isn't it massive overfueling etc that causes this sort of thing?

[Jer309GTi 3]

Isn't it massive overfueling etc that causes this sort of thing?

I think you're right there. Or could be headgasket (between combustion chamber and oilway) or worn piston rings.

[Anthony 1,003]

If it's misfiring badly enough then that will leave unburnt petrol in the cylinder(s) and some of that will find it's way into the sump, so over a few hundred miles will allow the oil to smell of petrol.

 

More likely though it's badly overfuelling as suggested above, which might also be the cause of the misfire.

 

Certainly I'd change the oil now as it's effectiveness will have been reduced, and I'd get to the bottom of it sooner rather than later, as if it's overfuelling that badly you're probably getting bore wash as well which won't be doing your rings/liners any favours at all....