Help needed: Oil in the coolant hose on a 1.5 TDI

Hello VW drivers, maybe you can help me out quickly?

Today I discovered that the air hoses connecting the turbo to the intercooler and from the intercooler to the engine were wet in several places with oil. When I opened one of those hoses using a quick-connect fitting, oil actually started leaking out! Then I checked several connections, and there was oil there as well.

That can't be good, right? It's not an oil cooler !
No, seriously. There should be no oil in the intake stroke. That means the engine is getting dirty air.

Does this indicate that the turbocharger is leaking? Where else does this oil come from?

I had already noticed in the workshop that this hose was 'wet,' but I thought at the time that it was probably from the oil change that had just been done.

Please advise me on how to be well-informed when I go to the workshop, because they often say here that something is 'not a big deal' or 'that's just how it is.'

Sure, here's the translation:

'Thank you in advance!'

Greetings, Sebastiaan.

Hello,

A small amount of oil in the intake manifold is normal because:
- The crankcase ventilation system outlets before the turbocharger.
- the turbocharger impeller is sealed with labyrinth seals, which, due to their design, cannot be 100% airtight.

But one thing is certain about your car: where the hoses were wet with oil on the outside, it's likely that oily intake air is leaking out under operation.
You're wasting power that way, and it puts more strain on the turbocharger.
You should check the hose clamps and replace any that are problematic with hose clamps.
With click-fit connections (which I haven't had the pleasure of working with yet), some kind of sealing is necessary, and I suspect it's done with O-rings. You should replace these if they are hard or cracked.

Best regards, Rainer.

Hello Rainer,
'As you describe it, that's exactly what I'm experiencing. The hose is really wet with oil at that click-fit connection, and the area underneath, where the engine manifold is, is also wet.' As I already mentioned, a significant amount of oil leaked out, not just two or three drops.

The click connections are sealed by O-rings, which look and feel good. However, there is always some play when you close the part again; it's just a bad solution. It's impossible to attach hose clamps there because the connections are made of aluminum.

Now I know why my car isn't performing at 100% anymore, and where I'm losing power.

Thank you for your answer Super.

Best regards, Sebastiaan[/img]

Hello,

There might be new O-rings available as a set from Volkswagen. The pipes must be leak-proof.
Too much oil: how many kilometers are on your car? Is the oil level above the maximum mark?

Best regards, Rainer.

Hi Rainer,
The car has now driven 56,000 km, but I've noticed the same thing before (at the VW workshop) at approximately 15,000 km. Back then, I didn't know which hose it was or where the oil was coming from. Oil level was not above the maximum mark.

'I think they really need to properly repair my car and make sure the intake manifold is completely sealed!' I now know enough to make sure that everyone does their job properly!

Why does VW allow the crankcase ventilation system to vent into the intake manifold? I mean, what business does oil have in an air duct? It just contaminates everything. Can the crankcase ventilation system be vented somewhere else, simply by disconnecting it and attaching a filter?


Greetings, Sebastiaan

It shouldn't be used in large quantities; this oil will be used to lubricate the valves and other components. So, it's actually not a good idea to completely turn it off; it should simply operate within the intended parameters.

Valve lubrication can only refer to the valve seat. The valve stem is lubricated.
Unfortunately, the valve seat experiences such high temperatures that the oil in that area would carbonize. 'This doesn't happen with oil, and it leads to black deposits.'

Okay, so my pipes are at least wet on the inside. Additionally, oil condenses in the intercooler. However, if you think about the airflow, you'll realize that the oil doesn't just sit in the intercooler. When there's too much, it gets swept away.

I wouldn't worry too much about where the oil is coming from right now. I would try to seal the charge air path and check the oil level more frequently. What you're observing could very well be normal.

Thank you for your contributions so far . You don't need to worry about the oil level; I check it every week. I always keep it at a minimum, below the maximum.

I have an appointment on Thursday to replace the charge air cooler hose and have the intake system checked for any further leaks.

Thank you again!

Regards,

Sebastiaan.

HI!

I had a similar problem: oil leaks were occurring at the clamps before and after the catalytic converter, and even the seal between the intake manifold and the air system was soaked! The cause was that the oil was too thin at high temperatures, and the oil level was slightly below the maximum mark at high temperatures, causing the oil to enter the intake manifold through the crankshaft ventilation system. The solutions are: 1) Install a mesh filter in the housing between the crankshaft ventilation and the cylinder head ventilation (or buy an older housing from VW, as it has the mesh filter as standard), which will trap the oil and allow it to drain back. Alternatively, 2) Remove the hose between the housing and the exhaust pipe, seal the hole in the intake hose, and place a small container under the housing to collect the excess oil.Collect the oil there!

Otherwise, I would go with Turbo!

Best regards.
Wolfgang.

Not bad, thanks, I'll check that out. Thank you, NVE!

Equip the housing between the crankshaft ventilation and the cylinder head ventilation with a grid.

Is this the black box located on the top of the cylinder head cover?

Regards,

Sebastiaan.

Don't forget the simple things. If the air filter is clogged, the turbocharger will also draw more oil from the crankcase.

I once looked it up in the book; one forgets things so quickly.

Okay, so it states that the oil is responsible for lubricating the valve seat rings, and the pressure regulating valve is responsible for ensuring that the oil flow doesn't exceed the maximum level (under normal operating conditions, when the oil is not exceeding its maximum level, etc.).

Is it possible for a pressure regulating valve to break down?