How to administer LLK (medication)?

Hello,

Since I'm still having problems with my A4 smoking, I wanted to check if the coolant reservoir cap is sealing properly... It's possible that it's leaking under pressure at the top (which you wouldn't necessarily see).

My problem now is the sealing. I want to seal the pipes, starting from the turbocharger all the way to the intake manifold.
How can I seal and make it airtight in a useful way?

A compressor is available.

Make a disc that fits inside the rubber tube and put a clamp around it.

The slide will likely be made of plastic and should, of course, have a certain minimum thickness.

If necessary, I could imagine using one made of wood, wrapped with Teflon tape.

One of the plates has an additional hole for applying pressure.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

So, I bought two end caps (drain plugs) for drain pipes at the hardware store.
They are available in sizes DN40, DN50, DN100, etc.
DN40 = 40mm outer diameter.
DN50 = 50mm outer diameter.

I disconnected the hose at the intake manifold and the one at the turbocharger (compressor, pressure side). Coincidentally, both had an inner diameter of 50 mm, which perfectly matched the DN50 size.

I installed a tire valve (the type normally used in rims for tubeless tires) into one of the two caps by drilling a hole with the appropriate diameter. The wall thickness of the cap is almost identical to the wall thickness of a rim, so the valve fits perfectly and is airtight.

Regards,
Jens.

brilliant idea, thank you!

Now I just need to get a valve.

... and do not pressurize it with 10 bar! !!!!!

mserge wrote:

.... und nicht mit 10 bar abdrücken !!!!!!!

"Starting at a pressure of 1.5 bar, the plug will pop out. The drain pipe fittings do not have any ridges; they are smooth."

By the way, there's a nice bang .

But not if he combines our ideas and securely fastens the DN50 parts with hose clamps.

Then, at xy bar, there's the LLK event - it probably sounds funny too .

m;
whose compressor doesn't turn off and bleeds air at 8 bar.

"No problem, I wanted to pressurize it with 2 bar and reduce the compressor's output accordingly. (Mine produces 12 bar, which would probably be even more fun )."

dieselmartin wrote:

But not if he combines our ideas and securely fastens the DN50 parts with hose clamps.

"In my case, even when the caps were securely fastened with clamps, they always popped out at 1.5 bar. The plastic pieces weren't any better secured inside the Samco silicone hoses. I had also previously degreased the insides of the hoses with gasoline."
I actually used a simple foot pump to press it down. That was perfectly sufficient; I didn't have to pump for very long.

Regards,
Jens.

Okay, I'll take a look tomorrow and try turning on the system. But that thing about using a foot pump is good; I won't have to adjust the compressor.

Hello, there's actually an even simpler way to do that (A).
Disconnect the hose/plastic tube connection just before it enters the aluminum intake pipe, at the spring clip.
2. Start the engine without pressing the accelerator; let it idle.
3. Manually hold the pipe coming from the hydraulic power unit (LLK), as the loader applies sufficient pressure, and even at idle, the pressure isn't excessive.
4. If something is leaking out, there's a hole somewhere.
That worked for my device, but unfortunately, there was a hole in the liquid cooling system.

It can also be done the other way around (B).
1. Disconnect the intake air connection again, this time between the turbocharger outlet and the intercooler.
2. Starting and idling - as above.
Then, hold the side that connects to the intake manifold/carburetor adapter/cylinder head again.
4. If the engine then shuts off, the connection is secure.
I also tried that, following method A. The result was the same as above: the engine didn't stall; therefore, I suspected a faulty coolant level sensor. After removing it, unfortunately, that wasn't the problem either.

Okay, I'm ready. Please provide the German text you want me to translate into English.

Okay, please don't follow the method of "vc," as there are several reasons why it might not be a good idea.

I don't think the first method is that bad because there's relatively little dirt up there that could get into the engine.
However, the second method is riskier because there might still be dirt on the lower lip area that could then be sucked up.

Besides that, both methods are not very informative because some leaks only occur at pressures of 1-1.5 bar.

I'm going to try and check my LL route today (I've been on a business trip the whole time...).

Okay, colleagues,
Firstly, MatthiasTDI96, I'm interested in knowing what the objections are.
'Some reasons against it...'
Without mentioning the reasons, it sounds a bit vague.
As a practitioner and someone who has been working on engines for 35 years, I always enjoy learning new things.
On the other hand, cksIT,
'Both methods are not conclusive because some leaks only occur at pressures of 1-1.5 bar.'
They are effective because they worked for me.
'Leaks that only occur at pressures above 1-1.5 bar are insignificant because the engine often operates within the intercooler pressure range below 1 bar of overpressure.'
'In many TDI engines, the maximum boost pressure set by the engine control unit (ECU) is not much higher than 1 bar (in what I believe are all engines up to 115 hp), such as in my 1Z and AFN models. To my knowledge, all engines up to and including the G4 have a maximum boost pressure of no more than 1.5 bar.'
4. Wenn man 1,5 bar oder mehr Überdruck per Luftpumpe einbringt, kann das System also bereits überlastet sein und Schaden nehmen, z. B. an der Verbindung zwischen der Plastik-Luftführung und dem Alu-Körper des LLK - dann hat man den mal eben kaputtgeprüft. Für diesen Druck ist das Drucksystem incl. LLK nicht ausgelegt, ein Druck von mehr als 1 bar Überdruck kommt ja betriebsmässig gar nicht oder nur sehr kurz (Überschwinger) vor. Hier Using a compressor is already quite risky due to the often poor pressure regulation of these devices.
It is absolutely essential to ensure that the boost pressure sensor is not included in the pressure test, as its standard maximum pressure is (usually) 2.5 bar absolute = 1.5 bar overpressure.
'3. Leaks that only become noticeable above 1 bar have practically no effect on the engine's performance – however, such 'holes' are rare. For example, a defective hose will always allow some leakage, with little pressure allowing less and more pressure allowing more. The same applies to a faulty coolant system. A pressure test, whether using my methods (which I don't claim to be particularly sophisticated; it's just based on practical experience) or with an air pump, is also informative even at lower pressures and should always be performed below 1 bar to avoid causing any damage.'
4. I don't want to criticize the air pump method; it deserves better, because when used correctly, it produces accurate results.
I wanted to present a 'quick method' that works without much effort – after all, no one is forced to pursue happiness.

To avoid misunderstandings: We are always talking about boost pressure here. VCDS displays the absolute pressure. To obtain the boost pressure, you need to subtract approximately 1 bar from the absolute pressure, and vice versa. The aforementioned boost pressures of 1 - 1.5 bar correspond to an absolute boost pressure of 2 - 2.5 bar.

Okay, I'm ready. Please provide the German text you want me to translate into English.

vc wrote:

They are effective because they worked for me.

For me, something that is truly reliable is something you can always count on. Just because it has worked in certain situations doesn't mean it will always work.

vc wrote:

"Leaks that only occur at pressures above 1-1.5 bar are insignificant because the engine often operates within a turbocharger pressure range below 1 bar of overpressure."

Okay, then I guess I have to look at the positive side: my car doesn't produce soot very often... it only happens during phases above 1 bar of pressure (which is every time you accelerate...).

vc wrote:

"In many TDI engines, the maximum boost pressure set by the engine control unit (ECU) is not much higher than 1 bar (in what I believe are all engines up to 115 hp), such as in my 1Z and AFN models. To my knowledge, all engines up to and including the G4 have a maximum boost pressure of no more than 1.5 bar."

So, there are some that are even original with a pressure of 1.5 bar (ARL has something like that, but I'm too lazy to look it up).
But putting that aside, many people in this forum don't use the original soft settings; instead, they use pressure levels ranging from 1.3 to 1.8 bar (or even higher).

vc wrote:

"If you introduce an overpressure of 1.5 bar or more using an air pump, the system can already be overloaded and damaged, for example, at the connection between the plastic air duct and the aluminum body of the heat exchanger – in which case, you've just broken it. The pressure system, including the heat exchanger, is not designed for this level of pressure; a pressure exceeding 1 bar is normally not present during operation, or only occurs very briefly (overshoot)."

"Sorry, but if the system couldn't handle it, nobody would start modifying it... I would have already changed all the hardware a long time ago in its original state. You can't just go on vacation without worrying that the system will break down! (You have to assume there are lower tolerance limits)."

vc wrote:

Using a compressor in this situation is quite risky, given the often poor pressure regulation capabilities of these devices.

If you only inflate the compressor to 2 bar, it's unlikely to cause much damage. However, if you have a foot pump available, that would also work!

vc wrote:

It is absolutely essential to ensure that the boost pressure sensor is not included in the pressure test, as its standard maximum pressure is (usually) 2.5 bar absolute = 1.5 bar overpressure.

Absolutely correct!

vc wrote:

3. Leaks that only become noticeable above 1 bar have practically no effect on the engine's performance – although such "holes" are rare. For example, a defective hose will always allow some leakage, with little pressure allowing less and more pressure allowing more. The same applies to a faulty coolant system.

I'm sorry, but that's also not correct! If I have a leak at pressures above 1 bar, it definitely affects me! Every time I accelerate, the pressure reaches 1.5 bar, and if there's a significant amount of leakage, the car will logically produce excessive smoke.
I've experienced this issue before as well. There was a crack in the hose. You wouldn't notice it when the machine is stationary, but under load, it would make a loud rumbling noise like a truck. It took me a long time to find it.

vc wrote:

A pressure test, whether performed using my methods (which I don't claim to be particularly sophisticated; it's just based on practical experience) or with an air pump, can provide meaningful results even with a slight overpressure, and should always be conducted below 1 bar to avoid causing any damage.

They are only meaningful if they reveal a leak; otherwise, there might still be one! And as I said, if this pressure is causing damage, something was already not right. It's better to discover it in the workshop than on your vacation trip.


I'm sorry, I don't mean to offend you, but I know a lot of older people around here who think they know everything... and they often pride themselves on the fact that they've been working on cars for a long time (which isn't necessarily bad when it comes to working with metal parts). I even ask my own father if he has any better ideas sometimes.

I finally found the time to do some work on the car...

Okay, the pressure test line is sealed. It held the pressure of approximately 1.5 bar for about 5 seconds (after which the plug blew out).

I then simply installed nozzles of the original size, and I still had the excessive soot (I revved the engine a few times while idling up to 2500 RPM, and afterwards there was a black spot on the floor with a diameter of about 20 cm).

I then obtained an original starter motor and connected it. It still made a clicking sound the first 2-3 times, but then it became less frequent.

Now I have a completely original system and very little soot. The question is, how much soot can be considered normal for an AFN engine with 240,000 km (approximately 150,000 miles)?

"When someone is driving with their high beams on behind me, I can already see what's coming out..."
I then tried a combination of 3, 8, and 10. Interestingly, the mass airflow sensor (MAF) showed a reading up to 1115. Could this be a problem?

I just wanted to make sure the system was verschandeln before I start modifying it again.