Loader lifespan: How long will it last?

Hello.

I have a 1999 Bora with an ALH engine. I've been experiencing the following problem for quite some time now.

When the engine is cold, it smokes white smoke from the exhaust and smells like burnt oil.
Der Motor lauft im Leerlauf mit leichtem Unterdruck ca. -0,02 bar. If you press the accelerator.
Then the vacuum pressure continues to increase to approximately -0.15 bar, and the smoke coming from the back becomes more and more noticeable. At around 3000 RPM, the vacuum pressure...
'When the turbocharger kicks in, the engine runs normally, with 0 bar of boost at idle and increasing boost with higher engine speed.'
increasing boost pressure. The same problem occurs when starting the engine immediately when it's cold. You're driving a naturally aspirated engine.
The turbocharger only starts to build pressure when you press the accelerator pedal more firmly. Otherwise, the engine runs without it.
Completely normal. Boost pressure at full throttle is between 0.9-0.95 bar. Oil consumption is approximately 0.1 liters per 1000 km. I use 10w40 Castrol Magnatec.

What's wrong with the loader, and what's the most reasonable way to fix it (repair or buy a new one)?


Regards,

Paul.

Are you sure that sufficient oil pressure reaches the loader quickly enough?

Mein AFN Lader (VNT15) braucht (lt. LDA Anzeige) im kalten Zustand im Leerlauf auch bis zu ca. 20 sec, bis Öl angekommen ist. Ich kann das auch an der LDA verfolgen. Gleichzeitig ändert sich das Geräusch der Hydros. KM: 270t, 5-40 oil.
During the colder months, I would switch to a 5W-40 oil.

These are my experiences regarding this matter.

Are you sure that sufficient oil pressure reaches the loader quickly enough?

Mein AFN Lader (VNT15) braucht (lt. LDA Anzeige) im kalten Zustand im Leerlauf auch bis zu ca. 20 sec, bis Öl angekommen ist. Ich kann das auch an der LDA verfolgen. Gleichzeitig ändert sich das Geräusch der Hydros. KM: 270t, 5-40 oil.
During the colder months, I would switch to a 5W-40 oil.

These are my experiences regarding this.

In your opinion, where does the oil go that the (mechanical) oil pump delivers from the very first rotation? Manufacturers specify that a sufficiently high oil pressure must be present within a fraction of a second, otherwise the durability of the ATL plain bearing cannot be guaranteed. An ATL bearing cannot withstand being without oil for 20 seconds multiple times. Furthermore, the level of boost pressure cannot be used to diagnose problems with the oil supply.

@ polo2f

Your description suggests damage to the ATL accumulator. The piston ring on the turbine side is likely also damaged. Depending on how long the charger has been running, and whether the rotating components have already made contact with the housings, a refurbishment might be worthwhile.

I'll measure the time tomorrow. It's easy to misjudge the time, especially when you're in a rush to get to work in the morning.

Otherwise, my anterior tibialis ligament probably already shows significant wear and tear.

'But I'm not getting any smoke yet. Instead, I'm only experiencing a delayed pressure buildup when I start the engine immediately, especially in cold weather.'

Normally, I'll let the engine idle at around 1200-1500 RPM and observe the pressure reading on the LDA. If the pressure doesn't increase further after about 20 seconds, I assume that the oil has successfully lubricated the ATL bearings. Then I'll start driving. During this time, the hydraulic lifters also stop making noise.

Hello Polo2f,

I never really 'felt' it before, but I did when I used an LDA.
After I installed it, I realized that the motor...
The first 30 seconds to 1 minute, or the initial surge of gas.
with the intake manifold pressure conditions you described.
'Charger acknowledged. The charger only started working after I pressed the accelerator pedal.'
come along.

As I understand it, and as I still believe, it's your motor electronics.
Absolutely not, there is no mechanical defect or lack of oil.

The lifters on my AFN didn't even make a sound for a second before...
The noise softened. As a layman, I assume this is due to...
to ensure the oil reaches the lowest point quickly, like in a loader.

The ARL, which exhibited the phenomenon described above, was available at that time.
He just couldn't get into a rhythm at the beginning. He simply gave up on the climb.
Despite the high RPMs and clutch abuse, it stalled after a few minutes.
He was a real old fossil.

Both things: the throttle reduces engine power for the first few minutes in extreme cold.
'And I suspect that the initial seconds of the 'vacuum' function are intentional 'gentle' programs designed by the manufacturer. Assuming it's operating like a turbo...'
Initially heats up, or a block of ice that can withstand enormous pressures and torques.
If that were the case, it would be understandable.
I'm simply assuming that, based on the temperature difference, the turbine blades are kept in a 'sailing' position to prevent the turbocharger from over-revving.
Therefore, it even acts as an obstruction to the intake air, which explains the vacuum.

These are pure speculations. Based on my growing experience as a diesel driver, I suspect only one thing .

For competitive reasons, a PD system would have simply been prohibited, as it involved accepting too many compromises that we didn't want to impose on our customers.

For me, after the 1.9-liter VP engine with 81 kW, there was nothing else that should be offered to paying customers, at least not in a standard production setting .

It's best to have your preheating system checked for proper function to address your smoking issue.
That should fix it. It can be observed regardless of the vacuum pressure.

Hi,

Quote:

I simply assume that, based on the delta temperature, the turbine blades are kept in a "sail" position to prevent the turbo from over-revving. Therefore, it even acts as a flow obstruction for the intake air, which explains the vacuum.

nix unterstellen, sondern einfach mal gucki gucki machen was die Verstellstange am Lader macht, wenn Du den kalten Motor anlässt... You'll be amazed.

Best regards, Rainer.

Rainer, tell us - is she going for maximum pressure boosting, I think?

Devilseye503 wrote:

rainer, tell us - is she going for maximum pressure boosting, I think?

At least in my experience (with AHF engines), I've never observed anything different.

Best regards, Rainer.

Hello,
What else can a regulation possibly achieve in this case?
Best regards, Günther.

Okay, mine is behaving exactly as Rainer describes. The control signal for the N75 valve also shows that. I logged the data during a cold start and then again afterwards.

"Definitely, every TDI engine exhibits turbo lag under load when cold. If it were only switching to a protective mode at idle, you would experience significant turbo lag with every change in load, which, in my opinion, would make the vehicle undrivable when cold. I'd be interested to see how such a protective function could be designed in a way that is user-friendly."

In the event of a protective circuit activation, only the casing would heat up, and the turbo would only run occasionally, which would likely significantly increase the wear and tear.

Perhaps someone can share their experience with a protective circuit and how it was implemented. I can't provide information for all types of vehicles.

If it were my vehicle, I would have the charger rebuilt. If I had to rev the engine to 3000 rpm every morning just to get it moving, the wear and tear on the rest of the engine would be too great to risk it.

Here's an idea from me, although I'm not sure if I'm right . How is the vacuum pressure? If the vacuum pressure isn't built up, but instead requires a minimum RPM, then even if the N75 and turbo are working perfectly, it won't make a difference.

Check if your brake is stiff and if the handbrake is engaging properly. It's worth a try, I think. Even if I'm completely wrong.

Herr Antje wrote:

What is the vacuum pressure like? If the vacuum pressure isn't established, but instead requires a minimum speed to build up, then even if the N75 and the turbo are working perfectly, it won't make a difference. Look, check if your brake is hard and if the VTG is tightened correctly. I think it's worth a try.

Yep, that's right.

Otherwise, a cold start MWB 11 log would be very informative.
If the usual low torque values are displayed in the LL (low-load indicator) and the RPM range, the MSG (Motor Software Generator) attempts to build up boost pressure, but it fails (due to a stuck VTG - Variable Turbine Geometry - or the turbocharger shaft being seized in cold, viscous oil).

Interestingly, I sometimes observed a similar phenomenon with my AFN: a slight vacuum on the LDA (Lambda sensor) after cold starts, until the first slight acceleration during driving.
As if the loading pump... see above. I would actually rule out a stuck VTG (variable torque generator), as I had installed the larger version.

I checked it.
Hydraulic lifter noise, lasting a maximum of 3-5 seconds, depending on how long the car has been stationary.
I agree that using LDA is necessary for creating a vacuum.

If I start driving immediately, there will be instant boost pressure.
'I've experienced temperatures below -20 degrees Celsius in the winter, and I've noticed that sometimes the oil pressure doesn't build up immediately when starting the car. However, I wasn't using a 5W oil at the time.'