Audi A4: White/Gray Smoke - What Causes It?

Hello,

"Recently, my Audi A4 2.5 TDI (year 1998), which is white/gray, has been emitting smoke while driving and also at idle. (It's quite a lot of smoke – people often point it out to me when I'm stopped at traffic lights.)"
I read the error memory, and there were no errors stored.
The electrostatic precipitator (ESP) was replaced with the new version (cyclone separator) 18 months ago.
The starting behavior and performance are okay.

P.S.
I've noticed that it seems like oil is leaking out of the front-most cylinder on the left side, right from the intake manifold, but that shouldn't be possible, should it?
I recently had a faulty crankshaft seal (at the front) that popped out, and as a result, the timing belt spread oil everywhere.
Now I'm not sure whether the noise is coming from the exhaust manifold or somewhere else.

What could be the cause of the smoke?

best regards
Michi.

Quote:

What could be the cause of the smoking?

- Diesel smells like diesel.
- Oil by oil.
- Water or coolant, depending on how much has already been filled .

-> Stick your nose in and first determine what kind of liquid has spilled there.

Best regards, Rainer.

I can already rule out water, as nothing is missing.
I already smelled something, but I can't really tell if it's diesel or oil .

Regarding diesel:
- Check the injection start control.
- Idle speed control. A leaking nozzle would likely cause noticeable issues.

Regarding oil:
- Oil consumption?
- You already have new cyclone separators.
- Turbocharger bearing support?
- Valve stem seals?

Best regards, Rainer.

"I disconnected the hose between the second LLK (likely referring to a coolant reservoir or similar) and the connecting pipe that leads to the intake manifolds, and I observed the following:"

- Hose slightly oily.
- There are significant oil and soot deposits inside the pipe.

I also disconnected the hose from the mass airflow sensor and noticed that there is no oil in this tube (except for a tiny amount just before the compressor wheel).

Am I correct in assuming that the turbocharger is broken and leaking oil?

michi22 wrote:

I disconnected the hose between the second lower cooling line and the connecting pipe that leads to the intake manifolds, and I observed the following: - Hose slightly oily.

It's normal because the turbo always releases a small amount of oil, and you have a crankcase ventilation system that vents into the intake manifold.

michi22 wrote:

- There are significant oil and soot deposits inside the pipe.

It's also normal due to the above reasons + EGR.

Perhaps we should create an FAQ section about ":roll:oil in the charge air cooler" because the same question keeps coming up. }

Take a look at the PCV valve (Positive Crankcase Ventilation).
Over time, it becomes clogged with felt-like material that accumulates and then these symptoms appear.
Here's a translation:

"What you can try is to remove the oil filler cap after driving for a while. If you hear a hissing sound (indicating overpressure), then it's likely the crankcase ventilation system."
The solution involves replacing the conventional gas-air separator (KGE) with a cyclone separator (AKE), which functions as a centrifugal separator and cannot become clogged.

Hello,

I've had the oil separator installed for approximately 20,000 kilometers.
When I reached into the pipe, there seemed to be quite a bit of oil in it (my fingers were completely covered -> pitch black).

I also did the "hiss test," and it didn't hiss for me.

I also smelled the exhaust fumes, but I can't tell whether it's diesel or oil.

@SoupOfTheDay:
Perhaps it would be possible for you to take a look at this, since you also live in Vienna. I would of course come there by car, wherever is most convenient for you.

"Sorry, I completely missed that you already have the cyclone separators installed."
Was the separator, including its bracket, replaced?

I would like to watch it.

Hello,

That's very kind of you to take a look at it.
Would you perhaps be available around 7:00 PM tomorrow, or sometime on Saturday?

The oil filter adapter was not replaced. I only installed this part:
B059 103 464 B

best regards
Michi.

Okay, the part number matches.
I thought it could only be replaced with the bracket. Apparently, it can also be done this way.

Tomorrow, I would be available from 12:00 PM to 1:00 PM.
I'm spending the weekend in Carinthia.
Which district would you be in?

Hello,

In the 11th district.
Although I work until the afternoon, my wife is home during the day.