Kompressionsdruck zu gering 2,5 TDI V6 AFB | Posts 32+

Could it be that your battery is a bit weak, and that's why the engine didn't reach a high enough RPM during the compression test?

Best regards,

@vikinger

No idea - I have an appointment at another workshop tomorrow morning - I will mention it to them.

Can a weak battery produce such low compression pressures during a test?

I was once told that this can sometimes happen... if the voltage is low and the starter motor therefore rotates relatively slowly, it can lead to incorrect readings.

It doesn't really matter, because you just keep activating the starter until you no longer see any increase in pressure!

Regards,

Manuel.

Hi everyone,

I just picked up the car from a place that specializes in engine modifications.
They measured the compression pressure through the injectors, not through the glow plugs like VW did.

The result: 34 bar in all three cylinders on the right side (next to the air filter).

He didn't want to measure the others, because almost everything had already taken 5 hours, and he thought that, given how the engine was running, it would take about the same amount of time.
They were using an analog measuring device. I now have a printout with 3 curves on it.

He said that the entire intake manifold was heavily rusted and oily, and that there was oil in the coolant reservoir.

What should I do now? Do you have any idea how I should proceed?

Unfortunately, I don't know anyone here who could help me break this down, or rather, he could help me with it .

I am grateful for any suggestions.

Remove the intake manifold and inspect it; if there's too much dirt, burn it out. Remove and verschandeln the charge air hoses and cooler. Then, reassemble everything and test it again. Oh, and a little oil will always get in there because the crankcase ventilation system connects to the intake manifold.

Best regards, WarLord.

@WarLord
'Hmm - cleaning would certainly be a good idea, but that only addresses the symptoms and not the underlying cause of the high oil consumption, blue smoke, and excessive crankcase pressure (270 mbar) back then. Or am I mistaken? Please correct me if I'm wrong.'

I'm concerned that I might have to drive another 2-3,000 kilometers and everything will be sealed again.

Then you just drive another 2,000 to 3,000 kilometers, and then we'll see what happens. As far as I understand it, everything should be fine with the new gearbox.

Best regards, WarLord.

Hi,

v6Motion wrote:

The result: 34 bar in all three cylinders on the right side (next to the air filter). He didn't want to measure the others, because almost everything had already taken 5 hours, and he thought that, given how the engine was running, it would take about the same amount of time.

"While it's annoying that you're only getting readings from 50% of the cylinders, I'd agree with the statement that the others are likely correct. You would definitely notice a significant imbalance in the compression values in the way the engine runs. Since the initial test didn't show any major deviations, just generally low readings, it's probably accurate."

Hello,

I'm wondering why you're still worried. According to your previous statement, the KGH pressure is now back within the acceptable range after replacing the oil filter module. This problem is known to occur in the V6 engine and is quite common. If the performance is normal and there's no excessive oil consumption, there's nothing wrong with the engine.
It is normal for there to be some oil in the intake manifold. In my opinion, the conditions during the compression test were simply not right. If the other workshop performed this test by checking the injector nozzles, I wonder how they did it, as they must have removed the valve cover ...

Sure, here is the translation of the text from German to English:

'Hello'

@vikinger

The thing is, this is the second time I'm replacing the oil mist separator. Last time, everything was supposedly fine afterwards. I just want to be sure that it's not something more serious. Now it's running smoothly, and the power box is disconnected for now.
The gearbox is still emitting smoke from the rear. During load changes, especially when accelerating heavily or using kickdown, it could still be within the normal tolerance range.
The entire intake manifold is also clogged with soot and oil.

I'm planning to deactivate my EGR system and verschandeln the intake manifold tomorrow - let's see how it goes.

Hi there,

My father had the same problem with the clogged oil separator. We even thought the engine was going to be ruined.
Since you've been driving with oil clouds coming from the exhaust for a while, quite a bit of buildup has likely formed. I don't know your usual routes, but I would suggest taking the A20 and then flooring it all the way to the Kreuz Uckermark to really clear out the engine (OFFTOPIC: or you could exit at Prenzlau and have coffee with your girlfriend at the Kap-Restaurant ...). The compression test showed that the engine is okay. If there are still blue clouds after that, the problem lies elsewhere.

Greetings.
Jean.

Hello.
I've reviewed the previous responses. Are you aware that there's a known issue with excessive crankcase pressure in Audis? With V6 TDI engines, the pressure must be checked during every inspection. There have even been cases where the engine had to be retrofitted due to excessive pressure, involving a replacement of the oil filter housing. The oil mist is not surprising with excessive pressure; the oil goes through the ventilation system into the intake manifold and is burned. I also can't imagine that the engine block is damaged, even with tuning. The problem with the camshafts is also not uncommon, and it affects multiple V6 TDI engines.

Well, you've certainly dug something up from the depths .

Hello there...

I had already written something about that topic in another forum .
For some time now, my AFB has been losing more and more oil. Now, it leaves unsightly stains after being idle for a while .
Currently, I still suspect that I am also suffering from AFB (Abgasrückführung) issues due to excessive crankcase pressure . In the meantime, oil is leaking from the valve cover seals, specifically from two seals in the valve cover for the injectors, and a little bit from the oil filter cap. That's what I could see... possibly also from other places. There is also oil visible between the cylinder banks...
I went to the 'friendly' doctor today, who initially sent me home... 'everyone is at the table.' I'll try to get my blood pressure checked again tomorrow.
I'm confused about two different specifications regarding the permissible pressure. One mentions 5 mBar, while another, found on Audi's website and in another forum, mentions 500 mBar! That seems like a huge difference... does anyone know for sure which one is correct?
Could it possibly be the cause of my problem, considering that it (still) doesn't burn any oil (at least not visibly)?
'If the pressure is too high, is it safe to switch to the other version of the 132 kW V6 engine? Does anyone have experience with this conversion, regarding adjustments or part numbers? I don't want to have the repair done by Audi, and that's why I'm looking for some tips for the conversion for my other workshop.'

Thank you very much.

DENNIS

Hi,
What exactly came out of it?
Best regards, Roland.