Undichte Kraftstoffleitung! Luftblasen! Keine Ahnung mehr! | Posts 16+

Hi,
The air is already in the line before the filter.

That completely contradicts:
I just checked that. The bubbles are not coming from the tank. I suspect now that it must be the connection in the engine compartment.

'Ulf said that if you have the long, transparent tube attached.'

Hi, it's me again. I've spent some more time with my car and I'm tracking down the air bubbles. After I pulled the fuel filter out of its bracket a little bit (about 3cm), there are no more air bubbles in the line between the filter and the ESP.

Is there a specific installation height required for the filter?

Greetings.
Patrick.

reuselkopp wrote:

Is there a specific installation height for the filter?

I don't know... apparently, by bending the pipes while moving the filter, you "accidentally" closed the hole through which the air is drawn in.
Probably a flexible coupling connecting a hose to a pipe.

I once had a diesel filter that was leaking. Whenever the car was parked uphill, it wouldn't start. Perhaps the bracket was putting too much pressure on the filter, causing it to leak.

Regards,
Andreas.

Hello.
I always slide the filter (from MAN) all the way to the end of the bracket. Tighten the bracket's screw gently, just enough so that the filter no longer rotates. No more tightening is necessary!
@ reuselkopp: I'm very certain that the short, black hose connectors that are directly connected to the filter are faulty.

Best regards, Robert.

@LZ,
"I've already replaced the angled connectors with a completely new hose from VW, but it's still drawing in air. I thought I had found something when I pulled the filter out a bit, but that feeling of success was short-lived. I don't understand it; it shouldn't be this difficult to get it sealed. Everything is new, but it's still leaking. The problem is that you can't pinpoint exactly where the air is being drawn in. As soon as there's any air in the system, it's constantly being circulated. If the air flows back to the tank through the return line, it's immediately sucked back in by the fuel tank sender. I think I'm going to switch to a complete PA hose system next, so I can get this sealed and immediately see where air is being drawn into the system."

Hello.

My Passat also has these "bubbles" as well, and it doesn't have any loss of power except for a "flat spot" around ~2800 RPM.

Best regards, Rüdi.

Hi everyone,
ich wollte euch mal ein feedback geben was sich bisher getan hat. Das Problem mit den Luftblasen hat sich erledigt. Keine einzige Blase wird mehr angesaugt. Yay...
I replaced the entire fuel line with a transparent PA (polyamide) line, and lo and behold, it's no longer drawing in any air. I purchased the 8mm ID line from www.drumm-gmbh.de, and I'm really impressed, especially considering that each meter only cost around €1.30.

Conclusion: The engine's performance has significantly improved, and the gray smoke has completely disappeared. Now, only a slight adjustment to the length of the VTG rods is needed, as the response in the lower RPM range is a bit sluggish.

Greetings.
Reuselkopp.

How can air get into the supply line if the return line is leaking???

Which return line are you referring to? For example, the one between the motor and the filter? Then, through the mixing valve of the filter.

Even if there is a leak in the return line between the engine and the filter,
There shouldn't be any air in the primary circuit.

Otherwise, the diesel filter wouldn't bleed itself automatically.
Or have I misunderstood something?!?