VTG Heißklemmer | Posts 32+

Hello, I've actually gotten used to the whistling/howling/hissing sound of the ARL, although I was a bit worried when switching from the relatively quiet ALH loader, as I thought it might not last forever. The car with 139,000 km (approximately 86,000 miles) has definitely seen some things, especially under the previous owner. (Was it modified with a "tune-up," and what was the driving style like?)
Here's the translation:

"The background to my log action is as follows: When accelerating slightly (throttle position around 30%) from 1st to 2nd and 3rd gear, starting at around 2000 RPM, you can hear, in addition to the noises already mentioned, a brief "grrrring" sound (1-2 seconds, getting louder with the engine speed). If I accelerate more aggressively, the noise disappears. I've intentionally triggered this a few times to try to pinpoint the source, although it was quite unsettling. I strongly suspect the turbocharger shaft is rubbing against the housing." I would prefer a gas turbine, if possible.
I haven't noticed any increased engine oil consumption. I probably need to take some more readings, but it's probably pointless if the VTG is already malfunctioning. I think it's slowly time to engage the turbo.
Rainer, is there anything decent available, or only large mechanical ones? Changes?

RedR32 wrote:

I think it's slowly becoming time for the turbo.

I don't think so. The VB loaders are very durable. Mine, and all the other commercial vehicles I've driven so far, have had that noise. At 139,000 km, it's barely broken in. I'm not familiar with that "grrrring" sound. Are you sure it's coming from the loader? If something is rubbing, you should be able to see it. Have you inspected the compressor wheel?

Hello Michael,

Quote:

If something is grinding, you should actually be able to see it. Have you ever inspected a supercharger

?
Easier said than done. But it's no use, I'll get started on it soon.
When installed, it's almost impossible to tell anything is wrong. Maybe I'll start small and test how far the loading arm moves towards the edge. However, I've also seen a new loading arm where the arm could be pushed almost against the housing with a little pressure. So, this test doesn't seem very promising.

RedR32 wrote:

When gently accelerating (approximately 30% throttle) from 1st, 2nd, or 3rd gear, starting at 2000 RPM, you can hear, in addition to the previously mentioned noises, a brief "grrrring" sound (1-2 seconds, becoming higher in pitch with the RPM). If you apply more throttle, the noise disappears. I have intentionally triggered this a few times to try to pinpoint the source, although it was quite unsettling. I strongly suspect the turbocharger shaft is rubbing against the housing. Ideally, it would be the turbine side.

Usually, the turbine assembly would immediately break apart if it were making contact with the housing. The fact that your charger still works actually proves that nothing is shorting out.
To check for proper operation, with the suction pipe disconnected from the compressor, you can manually rotate the compressor impeller and try to pull, push (this should not be noticeable), and tilt it (a slight tilt of about 1 mm is normal).
The open VTG design, without a vacuum, allows the impeller blades to be positioned "optimally" towards the turbine wheel, so that you may. You can also cause contact between these parts by tilting and rotating.

Okay, here's some new information from the 140,000 km ARL front: The deflectors have once again been significantly scratched on the housing; it's infuriating.
Since I had soaked everything in rust remover the day before, and the nuts were only lightly rusted, all the screws and even the loader housing came off relatively easily.
The wave doesn't seem to be affected by the game at all; there's nothing on the casing to suggest otherwise.
The VTG control rod is slightly bent.
There is a crack in the exhaust housing. Oil is leaking out from the screws on the side of the air intake.


I completely sanded down the exhaust housing, and the result is that the turbocharger now whistles much less than before; it's surprisingly quiet. I probably won't be able to do anything about the slight oil leak around the screws on the fresh air side, nor about the crack. I hope it doesn't grow any larger and stay within the exhaust stream.
The material choice for the exhaust housing is cheap.

The crack could be caused by excessive/poor tuning, immediately shutting off the turbo after a prolonged period of full throttle, or driving at full load quickly when the engine is cold.