Blue smoke while driving

Hello community,

First of all, I have great respect for the level of this forum! I've been an enthusiastic reader of the articles for quite some time. After searching through the existing articles for a while, I now need to reach out to you:
I drive a G3 GTI-TDI, first registered in 07/1996, with 122,000 km. After some starting difficulties following the recent very cold nights (the engine started immediately, but ran roughly for the first few seconds and emitted thick blue smoke when starting), I checked the glow plugs. And there it was: 3 out of 4 were defective! For some reason. Since the repair, all the problems have been resolved - there's only minimal blue smoke now, which disappears immediately.
This morning (outside temperature -4°C) on my way to work, the oil temperature was 60°C and the water temperature was about 50°C according to the dashboard display. While driving at a constant speed of about 60 km/h, I suddenly noticed distinct blue smoke in the rearview mirror, which clearly came from my car. I then briefly accelerated when the oil temperature reached about 70°C, and the blue smoke disappeared.
Has anyone here got an explanation for this? Unfortunately, I'm not technically inclined and can't figure it out myself, even after reading the available articles. Oh, and by the way: oil consumption is about 1 liter per 15,000 km.
Thank you in advance for your help!

Regards,
Marcus.

How much time/distance was there between the glow plug replacement and your observations this morning?

Hi,

Could it have been something like that?
Okay, I'm ready. Please provide the German text you want me to translate.

Hi,

Thank you for the quick responses!

@Julian
I would estimate it to be a maximum of 200 km.

@Ulf
That might be it. I wasn't able to reproduce this phenomenon when the engine was idling. While driving, I would say it was around 2000-2200 RPM.
If I understand the answers correctly, I have nothing to worry about, right? At least not as long as there are no other unusual symptoms.

Regards,
Marcus.

Oh... in that case, I would almost suspect residual condensate in the exhaust system. If possible, drive the engine until it's fully warm, and then drive a long distance (50 km) at a good speed on the highway. This should definitely get rid of any remaining condensate. (Check and top up the oil level before and after!)

If the problem persists, I would suggest:

- Valve stem seals
- Insufficient glow plug power supply (voltage, connections), afterglow not ensured.
- Charger compartment leaking / needs to be sealed.

Since you haven't complained about anything else with your vehicle, I assume there isn't a major defect, like a blown head gasket or something similar.

What oil viscosity do you use?

@Julian

Currently using 10W40. I once considered using 5W40 over the winter, but if I understand the general sentiment in the discussions about this topic correctly, it mostly benefits the oil seller, right?
Otherwise, I don't have any other problems, except that the engine doesn't really warm up properly in the current temperatures. In my opinion, the head gasket is still okay (no water consumption, no oil visible in the expansion tank, no white 'sludge' on the oil filler cap). But with 122,000 km, it shouldn't be defective yet, right?
The loader, surprisingly: this is already the third one, and it should actually be working properly.
Today (with a temperature of -7°C), the problem did not reappear.

Marcus_Nbg. wrote:

The loader, believe it or not: this is already the third one, and it should actually be working properly.

Öhm... Warum ist denn bei 122tkm schon der dritte Lader verbaut? Fahrweisenbedingt? Oder stimmt da evtl was mit den Randbedingungen nicht (Loch in der Ladeluftstrecke, Ölversorgung n.i.O., ...)? Nicht das der Blaurauch die Forderung nach einem 4. Lrepresents a vein.

Regards,
Sure, here's the translation:

"Guste" is a German word that means "gust" or "gust of wind." It can also be used to describe a sudden burst of something, such as laughter or anger.

Oil consumption is approximately 1 liter per 15,000 km.
Your engine is consuming more oil! Usually, the consumed oil is compensated for with water (N-oxidation), which indicates poor combustion! Assume that you mostly drive short distances... so don't go on the highway and "boil" the mixture! It's better to change the oil beforehand or gradually bring it back up to operating temperature!

@guste100
The turbocharger was replaced for the first time at approximately 80,000 km - after a long back-and-forth - mostly at the company's expense, because the VTG (variable turbine geometry) was faulty. It was made functional again, but the loss of performance was not permanently resolved. At that time, I was not aware of any larger vacuum leaks.
The second time, it was 'just in case,' because the car was still under full warranty and was experiencing reduced performance due to the mass airflow sensor. The VW mechanic said, 'then we'll be on the safe side.'

@silendwater
The oil consumption is accurate. I drive a relatively high amount of short distances, but also regularly use the highway, and quite fast when the engine is properly warm. Between oil changes, I've never had to add more than a liter of oil.
'If compensation were being achieved through water, wouldn't we see an increased water consumption? However, I haven't been able to confirm this; so far, only small amounts have been added, if needed at all.'

hello everyone

I'm experiencing the exact same problem here.
Mileage: 267,000 km. Oil consumption: 1 liter per 12,000 km, mostly long-distance driving. No short trips.
While observing the voltage from the quantity control, it was noted that the voltage was fluctuating constantly between 0.79, 0.8, and 0.81. It also exhibits a blue smoke, especially when cold. The injectors are new, the glow plugs are new, and the pump timing has been checked and is correct.
The car also starts to buck at engine speeds lower than 1600 RPM.

Is there nothing we can do?!

Best regards,
Eric.

FlatEric wrote:

The car also starts to buck at engine speeds lower than 1600. nothing to be done about it, right?!

Perhaps it is:
Okay, I'm ready. Please provide the German text you want me to translate.