Oil Separator: What is that black box on the cylinder head?

Hello,

I once looked at the round black box on the cylinder head of my car. I previously thought it was an oil separator or a pressure valve. However, as far as I could tell without damaging it, it only contains a thin membrane and a thin spring. When I blew air through it, the air flowed through all the openings. The connections to the cylinder head and the crankcase are directly connected by the mostly empty housing. The connection to the turbo comes from the center and could potentially be blocked by the membrane and spring, but as I said, it is also open.

My guess is that it's a check valve that prevents oil from being sucked in when the air filter is clogged.
Does anyone have a better suggestion?

'I'm concerned that oil is apparently entering the intake manifold through the crankcase ventilation system, and over time, this is filling up the intercooler, which reduces its effectiveness. I would therefore like to install an oil separator. Where can I find a suitable one? The one from the V8 TDI is probably too large.'

Do newer 4-cylinder TDI engines have anything special?
'I'm familiar with this white canister located between the crankcase and the cylinder head; it doesn't seem to do much. Is this an empty canister, or does it contain some kind of technology?'

Hello.
Wolfgang.

Hi Wolfgang,

According to the catalog, this is a pressure regulating valve. I'm not exactly sure what it does. There's a separate oil separator (which I don't have on my engine).
Is that the white can you're talking about?
1c ETnr: 052 103 495
The turbo will also inject a small amount of oil into the coolant.

Apparently, the Polo TDI also has an oil separator, but I can't find it. Maybe someone in the 165 forum knows where it is.

Regards,

Maciek.

Wolfgang, syncro16 wrote:

I'm concerned that oil is apparently entering the intake manifold through the crankcase ventilation system, and over time, this is filling up the intercooler, which reduces its function.

Hi,

remember that the oil mist has an important function: lubricating the intake valves .