Oil in the air cooler

Hello,

Yesterday, I accidentally discovered that some oil was leaking from the connection between the air-to-water cooler (LLK). Approximately 20 cm before the LLK.

How is this possible? The LLK doesn't actually have anything to do with the oil cycle.

Greetings

Hello!
Same for me!!!!!! I had already posted in the Passat 3B forum, with the result that the oil was normal, but not that it was leaking! Then I went to the workshop. There they removed the hose and about a teaspoon full leaked out. But it should be up to a tablespoon full (!!!) inside! This is engine oil vapor that then becomes liquid again. But it MUST be sealed. But it wasn't for me! The lowest point on the intake manifold was oily. But nothing has been replaced yet, just cleaned and lubricated at the seat. Let's see if this works better now.
Mine is also an AVF 96kW TDI PD, manufactured in 2002.

Greetings

Some oil is perfectly normal. The bearings of the turbocharger, which are supplied with engine oil, are never completely sealed. That is, some oil in the hose to the pressure pipe is perfectly fine. However, it should not leak out. This simply means that something is leaking. The connection between LLK/pressure pipe and the hose, as well as the two clamps, is particularly problematic. I replaced the clips with screw clamps because the connection on my Golf came loose once, and the pressure pipe on the oil pump's cam shaft 'broke'.

Alois wrote:

The bearings of the turbocharger, which are supplied with engine oil, are never completely sealed.

Hi Alois,

The oil mist in the intake area mainly comes from the crankshaft case ventilation and is necessary to lubricate the valve guides!

Alois wrote:

This means that having a little bit of oil in the line leading to the pressure pipe is perfectly acceptable. But it should not be visible to the outside.

exactly. The intake area must be airtight, otherwise the charger will get damaged

Na na... and as the engine ventilation ducts were still open to the outside, were the valve guides not being lubricated?

Hi Alois,

Back then, you also couldn't drive 15,000 km without refilling -> meaning the valve stems were constructed completely differently -> which allowed enough oil to pass through the valve guides.

......The oil mist in the intake area is mainly caused by the crankcase ventilation and is necessary to lubricate the valve guides!


Just a question: And how are the valve guides 'lubricated'?
They are not fresh air cooled and will become 'a little' hotter....

With burnt oil then or how?

Greetings
Michl

With burnt oil then or how?

MichlM wrote:

Just a question: And how are the valve guides "lubricated"?

Hi Michl,

legitimate question However, I am unsure...I only repeated what was in my clever book It says that the intake valves or passages wear out much faster than the exhaust valves without the oil mist. Maybe someone knows the answer

Hello!

The crankcase ventilation is purely for environmental reasons. The oil mist is simply burned off so that nothing can drip onto the ground or contaminate the air and engine compartment. The valves have nothing to do with this. Previously, lead in the fuel was the lubrication for the valves. The valves are also fitted with a seal on their upper surface, to prevent any oil from entering the guides.

Due to the use of very thin oils, especially synthetic oils, oil mist occurs very strongly and frequently, and is absolutely normal. You only notice it when the pressure range of the system becomes leaky, then you will see the oil traces. This has nothing to do with valve lubrication or turbocharger lubrication, so don't worry.

Of course, it shouldn't be too much oil, otherwise the cat could suffer a lot.

Greetings,
Peter

Thank you for your responses. I will go to the workshop today to have them check the clamp and possibly seal it.

The valves are also fitted with a seal on their upper surface, to prevent any oil from entering the guides.



Hello,

That's surprising to me, that the valve stems aren't being lubricated in their guides??

Greetings

Tobias

Hi,
A small amount of oil always passes through the valve stem seals. This can also be controlled to some extent through the quality of the surface.
"Excessive lubrication is not necessary either, because, strictly speaking, no force is transmitted from the valve stem to the guide when using a tappet."
If there is a connection between oil mist and wear, then it is at most the opposite: Because oil is already present, for example, one can save on the material.

Hello!

Yesterday, I was at the workshop because of the oil leaking from the LLK hose: This is normal and can sometimes happen. Oil should always be in the line (oil mist).
During the inspection, a new hose should be installed (under warranty).

Can the turbo actually "inhale" dirty, dusty air through the leak?

Greetings

Rudi

The aforementioned oil film is actually between ATL and LLK, or have I misunderstood something? Here, there is almost always a positive pressure in the atmosphere (so nothing can enter), and furthermore, the location is AFTER the ATL ('backwards' against the 'airflow direction'), so hardly anything can get through.
Workshop Statement: Of course, the oil mist is normal, but not the leak. Problems can arise if the loose hose completely slips off. I don't want to know the RPMs of the ATL when it's operating without any resistance.