General Catch can

[Mike1alike]

Nope, I'm just not buying this "it's in the air" theory. It just doesn't make sense. You're looking at the wrong data, like Sean Connery was looking when he was the Medicine Man (1992) and he finally discovered "It wasn't the bromeliad, it was the ants."


The air inside the engine is inside a seald system. And as I've mentioned, the water cannot get inside by osmosis, but it gets in somehow. If it was like you say it is, ALL ENGINES would present the phenomenon, not just some. And think about it, let's say the air does have the water to begin with, but then, when the air is put through the oil catch can system the water is separated and the air left should be dry.

@The Panda Nut , I ment to ask before, did you run just short drives there, getting all that water, or also longer drives?

 

[koalar]

The air inside the engine is inside a seald system

I top up with oil

Oil drains though the head through the block to the sump via gravity

The valve cover is connected to the air box via a pipe

It's not a sealed system

 

[Mike1alike]

I top up with

But not everyday. And where there's a catch can, it catches water at the same rate even when you're not topping up. So that's not it.

Oil drains though the head through the block to the sump via gravity

Yes, that is pretty much the system (plus the oil filter and inside channels). And it is sealed. If it wasn't, oil would be spilled out.

The valve cover is connected to the air box via a pipe

Yes, that is true. That might be the entry point.

 

[koalar]

Yes, that is true. That might be the entry point

There's 5 holes that run from top to bottom of the engine, all the oil and air is open to the atmosphere, it's not a sealed system , it's more like a sauspan, a byproduct of combustion is water You often see it dripping out of the exhaust and / or steam exiting the exhaust

It's not problem, most cars do it, most are worse in winter, most are worse if the car only does short runs

Corsa
A-Class
205

It only becomes a problem when it effect the MAP sensor as in case for the original poster

Which is rare when the car is new, leaks and blockages in the vacuum side of the emissions control side being the most common cause

 

[cooperman]

Might help the explanation

 

[PuntoHowTo]

Engine gets hot, air inside it expands, hot air is able to hold more moisture than cold air.

Stop the car, the air inside the engine contracts as it gets colder again, as it contracts more air is pulled into the engine which also contains moisture.

Cold air is not able to contain as much moisture as warm air and as a result the moisture condenses out on the inside of the engine and runs down into the oil. You start the car the crack whips it up into a nice emulsion of oil and water. As it heats up again the water starts to evaporate into the crank case air again, and is pushed out of the breather as the air expands again.

If you think an engine is a “sealed” system then look what happens when a car turns over.

It’s only sealed in the context of oil not pouring out of the bottom, the top is not sealed.

 

[Mike1alike]

Yes, I got that. My bad! Thank you all for the explanations, especially @koalar. Cheers!