Blue smoke from turbocharger: What it means

Hi everyone,

After a short period of use, my engine starts to smoke.
More precisely, it seems to be emitting smoke somewhere near the engine.
Es kommt aus der Richtung des Turboladers. I got this...
I took a closer look, and there are actually small bubbles coming from the intake manifold on the left side when you're standing in front of it. Could it be that they evaporate on the turbo or some other hot part, causing the smoke?

How does something like that happen?
What can I do?

It's an AFN 81 kW engine in a Corrado.

Thank you for your help.
Arne.

...if your intake manifold is not properly attached to the cylinder head, or if the gasket between them is defective, oil will leak out. This oil then enters the intake manifold through the crankcase ventilation system.
Please pinpoint exactly where the oil is leaking; it wasn't clear from your description, and we don't want to assume your head gasket is faulty...
If oil drips onto hot parts like a turbocharger or exhaust, it will produce smoke.
Just for your information: evaporating oil also burns quite well...

Best regards, Rainer.

Thank you for the quick response, Rainer.
I will try to locate the spot.
However, it's not quite easy to reach that area behind the engine.
I will clean everything up, and then we'll see.
comes from.
Okay, and one more thing... if I lift the lid on the...
Oil filler cap.
There's a bit of white foam there... I heard that could be...
Could it be a head gasket issue?!? The engine has been sitting for 2 years.
Maybe there was still some water or something 'inside'...

I am grateful for any response.

arne

... can be normal if the car has mostly been driven in city traffic and has never really warmed up properly.
You really have to see it to understand it, so it's hard to judge from just hearing about it.
Make sure to check the coolant reservoir for the correct level. If you're losing coolant and there are no visible leaks, you can be sure where the white foam is coming from: it's likely due to a faulty head gasket or a cracked cylinder head.
You should definitely change the oil, and then drive the car properly to get it hot, which will help to dissolve any sludge and evaporate the water content in the sludge.

Best regards, Rainer.

Hi,
The brown sludge can also be caused by condensation (especially in winter / when the car is not properly warmed up frequently).
Hopefully, you changed the oil (with filter) if the engine has been sitting for two years.
I would then change the oil and filter again after another 1,000 to 2,000 kilometers, before switching to the regular maintenance interval.

Hello Arne!

I recently encountered the same problem with my...
AHU engine in a Passat.
I noticed it after periods of acceleration followed by coming to a stop at traffic lights.
For me, it was the air hose connected to the turbo (coming from the intercooler).
It's attached to my turbo with two hose clamps, and those were just loose!
The fatal thing about it was/is that there's something underneath the hose.
flexible intermediate section (mesh) connected to the exhaust, and it was emitting a lot of smoke.
Schrauben festgezogen und aus die Maus! Kein Qualm! No smell!
Maybe this will help you!

Regards,

Andreas.

- The car had driven 95,000 kilometers in 2 years. I think it always reached its operating temperature properly.

- I certainly hope it's not the head - that will definitely be expensive. I'll try to take a photo with the digital camera of the smoke and the intake manifold in the next few days.

- Yes, I changed the oil and the filter. And after 20 minutes of the engine running again... because a piece fell into the oil pan when the transmission was removed...

I'll try to document this for you somehow.

Thanks and regards,
Arne.

Actually, this is a well-known problem.
The intake manifold bolts tend to loosen on AFN engines.
'Tighten the screws, and then it should (if the turbo isn't broken) ...'
The problem should be fixed.

Yesterday, I got behind the wheel again and really pushed the engine. And... there was blue smoke again.

The smoke is coming from below the exhaust manifold - I think it's originating somewhere above the turbo. Where is the oil leak, and why does it only smoke under heavy load? If I let the engine idle for 1 minute, the smoking is almost gone.

All the screws on the intake manifold are tight.

What do you think - how should I proceed now?

Thanks,
Best regards,
Arne.

Get a motor wash and then really 'kick it' afterwards.
Then you should be able to see where the oil (or whatever it is) is coming from.

From the top, you can't see anything - I cleaned everything with brake cleaner yesterday and then set it on fire.

I'm going to try using a mirror in the next few days to locate a leak that isn't immediately visible.

Or does anyone have any other ideas?
I am grateful for any advice.

Arne.

Hello Arne,


What was the cause of your problem back then?

The engine block is wet with oil, and it looks like it might be coming from the head gasket, but it could also be coming from the intake manifold. It's hard to tell exactly where it's coming from due to the limited space.
And there's only a little bit left in my brake cleaner bottle - it's not enough for a complete engine cleaning.

Apropos Motorwäsche - irgendwelche Tips vom Experten? Dampfstrahlen ist ja sicherlich nicht so toll, auch wenn man den STrahl nicht direkt auf die LiMa oder Steckverbindungen hält. WWhat do you mean?

Best regards, Georg.

Hi Georg,

'That problem had resolved itself back then. Maybe I used a different type of oil at the time. Eventually, the smoking stopped. I had a similar issue with my previous TT. It was under heavy stress, and there was oil smoke coming from the direction of the turbocharger... strangely, it also disappeared on its own. So, unfortunately, I can't tell you what the cause was in my case.'

Regards,
Arne.