Air Bubbles: Find the Root Cause & Fix It! (Solution)

Hello everyone,

After a long search, I think I've found the solution to the air bubble problem in the diesel line, which probably applies to many other situations as well.

In my case, the formation of bubbles wasn't extreme, but it was always present.
After unsuccessfully searching for leaks in the diesel lines, I realized that air might be being sucked into the system through the weakest point if a vacuum formed in the tank. This would explain why no actual leak could be found. So, I simply opened the fuel cap, and sure enough... the bubbles disappeared.

Behind the fuel tank lid is a valve that vents the tank. I removed it and checked it. It was stuck!
I cleaned it and lightly applied some 'diesel'.
The bubbles are gone now.

P.S.
During the AC service yesterday, it was found that 65% of the refrigerant was missing. The car is only 4 years old.
You might also want to have the system checked if it's not cooling properly.

Hi,
P.S.
During the climate control service yesterday, it was found that 65% of the refrigerant was missing. The car is only 4 years old.
Perhaps you should also have the system checked if it's not cooling properly.

I did that before spring as well.
Approximately 40% of the parts were missing from the Audi, which was over 9 years old.
However, the climate control system was terrible.
Now, after being refilled, the device cools down exceptionally well.
Much better than the air conditioning in the golf course clubhouse.

flightmaster wrote:

, it is possible that air is drawn in through the weakest point in the system when a vacuum forms in the tank. Consequently, no leak can be detected. I simply opened the tank cap and, lo and behold... the bubbles disappeared.

Hi.

A good tip that, in my opinion, could also help other people struggling with similar issues.

@Rainer: This is a case for the error database or future tips and tricks section.