What's the cause of white smoke and emulsion on the on the inside of the oil filler cap?
What is the cause of white exhaust smoke, even when the car is warm, from my 2008 Renault Modus 1.2 petrol with 32,000 miles on? There is also a small amount of emulsion inside the oil filler cap but no sign of anything unusual on dipstick or in the water reservoir.
Assuming that the engine runs okay, if you do quite a few short runs in the car (and not many long ones) this can cause condensation in the engine resulting in emulsified oil. You can clean it out and take the car for a decent long run afterwards and it should improve. However, the white smoke might also be water condensation, which is much more apparent in the current cold temperatures.
Answered by Alan Ross on