TDI Passat: High Smoke Value in Emission Test

Hello,
I'm having an issue with the automatic transmission in my VW Passat TDI, manufactured in 2003 and with 140,000 km on the odometer.
"During the inspection in December, the turbidity value was 1.8. The target value according to the sticker is 0.8. Subsequently, I added LM Diesel System Cleaner to the fuel tank and drove the car at high RPM on the highway. Otherwise, I mostly drive short distances."
The retest yesterday showed a value of 0.9. So it's still too high; no sticker.
It was noticeable that the car only reached a water temperature of 80 degrees Celsius when accelerated on the test stand.
The thermostat needs to be replaced now.
Is there anything else I can do?
The air filter is new, and the oil was changed 5000 km ago.
Diesel filter being replaced (cause unknown).
Before the inspection (AU), I added some LM Rust Stop to the fuel tank.
It is often said that 2-stroke oil can help. How much should one add?
What do you think about those additives that are poured into the oil before an oil change? After letting the engine idle for 10 minutes, the mixture is drained and new oil is added.
I wonder why VW sets such a low emission limit that seems difficult to achieve in practice. For Euro4 standards, the limit is 2.0.
Does anyone have any other ideas? Would an oil change help?

Tip: Find a workshop that doesn't use the often unattainable emission test value typically used for vehicles without a DPF, but instead uses the significantly higher value listed in the vehicle inspection documents (which are provided by the vehicle manufacturers).

Furthermore, the opacity value also depends on the throttle response of the person performing the inspection. If the accelerator is pressed too quickly, there will be an excess of fuel, which results in a higher soot content in the exhaust gas.

A new air filter can help, and a splash of two-stroke oil in the diesel fuel might also be beneficial.

Quote:

After that, I added LM System Cleaner Diesel to the fuel tank and drove the car at high RPM on the highway. Otherwise, I mostly drive short distances.

Schonmal nicht schlecht, aber: Wenn man überwiegend zart unterwegs ist und dann bei der AU das Gaspedal durchgetreten und der Motor an den Anschlag gejubelt wird, kommen die Ablagerungen der letzten x-tausend km aus dem Auspuff. All of a sudden.

Therefore: There are plenty of mountain roads in Austria where you can really accelerate. Let the engine run at higher RPMs for a few kilometers with full throttle, so that all the accumulated gunk from driving slowly is blown out of the exhaust system.

Also, check the intercooler piping for leaks (which can be identified by oil seepage). The TDI engine in the Passat 3B, especially with its long intake passages, is particularly prone to this issue.
If you're driving next to a wall with the passenger window open and you hear a hissing sound, you definitely have a leak.

Best regards, Rainer.

berndr56 wrote:

Hello, I'm having an issue with the automatic transmission in my VW Passat TDI from 2003... What do you think about those additives that are poured into the oil before an oil change? After letting the engine idle for 10 minutes, the mixture is drained and new oil is added. I wonder why VW sets such a low emission limit that seems difficult to achieve in practice. For Euro4 standards, the limit is 2.0. Does anyone have any other ideas? Would an oil change help?

Hello,
I also drove a 2003 AVB for many years and never had any problems with the emissions test, whether it was without or with an added, unregulated DPF. In my opinion, the requirements were easy to meet!
"Driving slowly for a while and then going full throttle during the test is probably not ideal. It's therefore not wrong to give it your all before the exam. However, extravagant actions are unnecessary."
Another oil change just 5,000 km after the last one won't do anything to address any cloudiness issues, and I don't think additives in the oil are helpful (and some of them may remain in the residual oil that stays in the engine when you drain it!).
Therefore, it is essential to follow Rainer's suggestion regarding a potential leak in the charge air cooler system and, if necessary, measure the mass airflow sensor (MAF).
Is the exhaust smoke visible when accelerating while driving?
haithamina

No, the soot is not visible. Now it has also been noticed that the engine temperature does not reach 90 degrees Celsius.
The thermostat is available for exchange.
I didn't understand the part about the intercooler system.
Driving with a window open next to a wall?

If the intercooler piping has a leak, air will escape, resulting in an imbalance between air and fuel in the cylinders that favors the fuel. This leads to increased soot production. Therefore, replacing the air filter is not necessarily the solution.
Furthermore, AU devices in Germany recently received a software update based on the new guidelines. It's possible that there might still be some minor issues or inconsistencies here and there.