Luftblasen im Diesel, Tankanlage defekt? | Posts 32+

Aloha, Flightmaster!
Well, "foam" was a bit of an exaggeration, but there were definitely quite a few bubbles.
The filter is brand new again; I already replaced the previous one after 1 year, or approximately 20,000 km. That didn't really help, but it was during the winter, so the diesel viscosity was a factor. These things seem to fit together quite well, because right now I only have 10-12 liters in the tank, the temperatures are moderate, and it's dry. When it's really cold, there are no bubbles; the VWV (presumably a system or component) activates, and then there are bubbles. After a while, there are either no bubbles or very few. Either the filter was properly bled this time (which it's supposed to do, but it doesn't work very well in practice), or the diesel has become thin enough through circulation. This might also explain the occasional "stuckering" (likely a misinterpretation of a sound) I've experienced on the highway twice before. I'm having trouble piecing together the exact sequence of events from memory, but it's quite possible that a) the fuel tank was often quite empty and b) there was moisture present in certain areas. It's conceivable that, due to evaporative cooling on the tank (I never experienced this during summer thunderstorms, but rather on quite humid days), the diesel temperature in the engine compartment decreased, the oil viscosity increased, and that at a high fuel flow rate at a speed of approximately 130 km/h, a large number of air bubbles formed. These bubbles overwhelmed the pump's venting capacity and traveled towards the injectors, potentially even triggering the NOx sensor (I had one error code stored once).
"If it were a little easier, I would get a piece of clear tubing to put in the section of the intake line before the filter. If the water goes in clear and comes out bubbling in the intake line, then at least I would know where these things are originating, although it would still be questionable why. But then I would be able to see it." Perhaps I'll try contacting Drumm ("Schnipp") again.
Okay, I can still do a little searching and experimenting: check the hose, open the fuel tank sensor, and try that "sealing" thing.
Okay, so tomorrow we'll start by replacing the remaining two engine mounts, then we'll move on to a motor checkup, and after that, we'll do this. Let's see...

Best regards,
Torsten.

Edit: Okay, it's Monday morning, I just had a quick phone call, and it seems like it will work out. It looks like a good source. I'll get the measurements taken today, and then the first thing I'll do is replace the front and rear sections of the DiFi (differential) to the tank with clear pieces. I believe that both are, to some extent, interchangeable, meaning that there is already a transition between them.