2.0 TDI Smoking: Causes & Fixes for City Driving

Hello,

Our Seat Altea 2.0 TDI is emitting smoke in stop-and-go traffic. Otherwise, the engine runs normally with full power.
At Seat, they found no fault and claimed that I had modified the car's engine control unit (ECU), which I have not done.

It's probably clear that diesel fuel is evaporating, but the question is why.

Thank you in advance.

Hello,

smell the exhaust and determine what the smoke is made of.
- Diesel (extremely bad, as it would indicate a faulty common rail injector and the engine would run very poorly).
- Coolant -> What does the coolant level in the expansion tank indicate?
- Engine oil -> usually indicates turbocharger damage.
- If available and active, the auxiliary heater (standing heater) may also produce smoke.

Best regards, Rainer.

[Translating...]

Hallo,
das dürfte das gleiche Problem sein wie bei mir. Also kein Diesel sondern Öl, beißender Gestank. Lies mal meinen (z.T. älteren) Beitrag: https://community.dieselschrauber.org/en/viewtopic.php?p=246347#246347
Besonders meine jüngeren Ergänzungen.

Gruß

Andreas

The pungent smell comes from poorly burned diesel fuel, not from burnt motor oil. You can easily distinguish the two smells.
hg
Herbert.

Hello...

Have you ever looked at the engine case ventilation?
"This thing tends to get really muddy quite often, especially if you frequently ride in urban areas..."

Exhaust Gas Recirculation (EGR) return pipe...

Both can be done quite quickly.

As my colleague already mentioned: Does he need coolant?
Starting behavior in the morning? -> If it starts poorly, you might have a hairline crack on the intake side -> not good -> replace the cylinder head.

If it's only losing coolant, the prime suspect is usually the EGR cooler (-> replace it). If that's not the issue, then there might be a crack on the exhaust side -> like mine had. In that case, you can add two cans of "radiator sealant" and it should stop leaking, at least temporarily. Mine has been doing this for 200,000 km, and now has 402,000 km with a chip tuning to about 175 hp...

Otherwise, I would take another look at the LLR (likely referring to a specific component or system). Also, I should measure the diesel pressure of the tandem pump and check the oil level more frequently. Eventually, the tandem pump will fail, and then you'll have 10 liters of oil mixed with diesel inside, resulting in a real self-ignition issue.

Hope I was able to help you.
Have a nice day.
Manfred.

Hello Manfred, thanks for the tips. But I've actually been dealing with this for quite some time already.
The expansion valves were/are completely clear on both sides. There is no coolant loss, and the engine starts and runs normally so far.
If a hairline crack in the cylinder head is responsible, it would have to be located between the intake side and an oil channel. Because older TDI engines (the ones that smoked heavily) also consistently exhibited noticeable idle fluctuations. This indicates that something was entering the combustion chamber, which, in my opinion, was engine oil (these engines tended to consume more than usual, but still within a moderate range).
So, after a long search, in my opinion, only these two latter causes remain, with the tandem pump being my "favorite." And I will definitely look into that one when I have time.

Hello,

Have you ever replaced the PDE wiring harness? It doesn't necessarily last "forever"... and considering the age of the vehicle, that might be the case.

Sure thing! Please provide the German text you would like me to translate into English. I will only provide the translation without any explanations.
Manfred.