Oil Mist Prevention in Intake Systems

Hey everyone,

I'm experiencing significant problems with oil in the intake system of my AFN engine, which is installed in a T3 van. The intake side of the new turbocharger and the intercooler are quite oily. It's supposedly "normal" to have some oil there, but in my case, the oil is actually dripping out of the hoses (when they are disconnected). This isn't good for the efficiency of the intercooler, which is already problematic in a T3 anyway.
The engine is mounted at a much steeper angle in the T3 than in the Golf & Co., and the crankcase ventilation system (pressure regulating valve on the cylinder head cover) seems to have problems with this. I already retrofitted the expansion tank between the engine block and the cylinder head (from later years of the AFN), but it didn't help .
What measures could I take to stop the oiling?
Venting the crankcase to the atmosphere (possibly with a small oil separator in between) instead of into the turbo's intake manifold? Would that work, or does the TDI engine require a certain amount of "back pressure" in the crankcase?
The pressure regulating valve would still be present, but atmospheric pressure would always be applied. I'm not sure how much vacuum exists on the intake side of the turbocharger.
If it's not possible to vent the system outdoors, are there more efficient oil separators available than this standard, low-quality part?
By the way, my EGR valve has been removed.

Thank you and best regards.

Releasing exhaust gases directly into the atmosphere would be quite messy and has been prohibited for environmental reasons since the mid-1960s. This is not only due to the oil content but also because the blow-by gases contain a high concentration of pollutants, as combustion near the cylinder walls is often incomplete.

Hello Jens,

Are you sure the engine is mechanically sound? I have personal experience with a 1.6 T3 naturally aspirated diesel where excessive pressure built up in the crankcase. This pushed the oil dipstick out, causing oil to leak from there. The dripping oil was then blown away by the wind and deposited on the tailgate as a nasty oily film (which is very common on T3s). I also experimented desperately with the crankcase ventilation system until it turned out that the worn piston rings were the cause.

If the valve cover from a 1.6TD T3 would fit on an AFN engine, it would at least solve the problem of the tilted angle, because, as far as I remember, it's shaped in such a way that the control valve sits horizontally again.

Regards,
Thomas.

Hi Jens.

The engine is mechanically fine; the problem isn't related to that.

Regards,
Jens.

Hello Jens,

What is your oil consumption per 1000 km?

Best regards, Rainer.

The oil consumption is approximately 1 liter per 10,000 kilometers, which translates to 0.1 liters per 1000 kilometers. I also cannot detect any signs of excessive blow-by.

Regards,
Jens.

I would just let it go through the long-life coolant without much worry, given that the consumption is only 0.1 liters per 1000 km.
It would be better if you fixed the leaks where the oil is dripping from.

Best regards, Rainer.

Hello!
"I tried that too, but it always blew out the turbocharger boost hoses. They were so damaged they couldn't hold pressure anymore. Someone advised me to replace all the clamps with proper hose clamps because supposedly the clamping system can't handle high boost - which I think is nonsense. In my opinion, it's technically flawed to pump soot and oil through the intake manifold; it really messes things up! So, remove the EGR valve and the crankcase ventilation system, and he'll thank you for it!"
Remove everything, verschandeln it with gasoline, vent the oil drain outside (or use an oil separator if that makes you feel better), and that's all there is to it! No more mess!
"I've been driving for thousands of kilometers like this, and I always enjoy seeing the dry hoses whenever I work on the suction system!"

PS: I'm sure I'll hear the usual complaints again about things like "leaky lips" in the turbocharger and so on, but I've already heard it all before, and after thousands of kilometers, I haven't noticed anything (except for slightly better acceleration in the partial load range!).

Sure, here's the translation:

"Hi, how are you?"

mozz wrote:

...take everything off, verschandeln it with gasoline, vent the oil breather to the outside (or use an "alibi" oil separator if that makes you feel better), and that's the end of the mess!!!...

There are people who simply aren't into "outdated models."
If you park your car on public areas, you can quickly get into trouble due to oil droplets on the sidewalk.

Best regards, Rainer.

Then just put the hose into an old oil can and empty it when needed .
and yes, I park in a public area, but there are hardly any drips there. I made sure that the hose is positioned where the condensation from the air conditioning also runs down, so it's impossible to leave a pure oil drip .
Sure, here's the translation:

"gruzz" translates to "greetings" or "regards" in English. It is often used as a casual way of saying hello or goodbye.

ps: I knew you'd crack under pressure *lol*

Rainer K.
I would just let it go through the long-life coolant without much worry; I wouldn't stress about it too much.
It's better if you fix the leaks where the oil is dripping out.

Hello Rainer,
During operation, nothing leaks out; it only drips when I loosen the hose clamps. However, I don't like it when the cooling liquid's effectiveness is limited by an oil film. In the T3, you already fight for every percentage point of cooling liquid efficiency, so it's really annoying to lose some unnecessarily. In the truck sector, there are centrifugal oil separators that sit between the crankcase ventilation and the intake manifold. They work very well, but unfortunately, they don't fit in my engine compartment .
I once disconnected the crankcase ventilation system and led it outside (of course, I plugged the hole in the intake manifold), but that resulted in some very strange effects. The engine started to produce an incredible amount of smoke at idle after about 1 minute. Hardly anything came out of the crankcase ventilation hose, certainly no noticeable amounts of oil mist. I couldn't explain it back then, and I didn't pursue it further due to other projects. Now, however, I have some time to dedicate to this problem .

Regards,
Jens.

Quote:

About a year ago, I temporarily disconnected the crankcase ventilation system and routed it outside (of course, plugging the hole in the intake manifold), but that resulted in some very strange effects. The engine started to produce an incredible amount of smoke at idle after about 1 minute. Hardly anything came out of the crankcase ventilation hose, certainly no noticeable amounts of oil mist.

"That's strange... uh, by any chance did you accidentally block the crankcase and leave the intake manifold open?"
and nothing is spraying out of the hose, and you barely notice the fumes that are coming out!

Sure, here's the translation:

"gruzz" is a German slang term that can be translated as "greetings" or "regards." It is often used in informal settings, such as text messages or social media posts.

To Mozz:
I already did it correctly: I opened the crankcase and connected the intake manifold.

Regards,
Jens.

I actually find the crankcase ventilation system integrated into the intake manifold quite practical: You can often tell where there's a leak by looking at the oil seepage .

Best regards, Rainer.

I once, about a year ago, temporarily disconnected the crankcase ventilation and led it outside (of course, I plugged the hole in the intake manifold), but that resulted in some rather strange effects.


Is it possible that the crankcase is leaking somewhere, and that the turbocharger could then draw a significant amount of air through the case? If so, there's a possibility that it could suck oil along with the air.

We once had a faulty oil dipstick tube that wasn't really leaking outwards because everything was getting sucked in instead... it was quite strange.

CU Gremlin.

It might be a crazy idea.

You install a small container at the lowest point of the intercooler system where oil can collect. You then attach a hose to the bottom of this "collection container" that runs back to the engine/valve cover.

When the bus is stationary, the oil drains down to the lowest point.
As soon as the engine is started and there is boost pressure, the oil is blown back into the engine.
If you don't make the hose too thick and potentially add a restriction, you shouldn't experience any significant pressure losses.