[Olivier A]

This might be usefull to someone, this is what I could see today following some bubbles... Its an odd path.
Feel free to point out any booboo...
Oh, its done with paint and the mouse, then crap, but you get the point

 

[Plutoe]

Wada 605/606 IFI bubble test guy!! That's sticky material!! What happens next!! I mean to the bubbles??

 

[Olivier A]

I think the bubbles just got expelled back in the tank via the return line.

 

[Plutoe]

Can the bubbles be captured and used elsewhere in the car or are they lost forever.

 

[Olivier A]

well, you might do something with, but I am not sure what yet? Following the path can keep you busy for awhile, this might be good? You can count them, keeping you busy?
There is alot you can do with the bubbles.

 

[Kajtek1]

I did figured it out in the past, but don't think you really need the info for repairs.
What is a bit confusing that the prefilter and main filter are in the same housing, while the prime pump between takes 2 tubings. Than shut off valve has 2 stages. I assumed this is safety measure. Older diesels have manual levels for shutting off in emergency.
That makes for a small maze, what would not be a problem would the MB used the eyed ends like in the older designs, than the weak orings.

 

[Olivier A]

Those Orings are indeed a nightmare. Grrr...

 

[Kajtek1]

Only if you don't do them right the first time. I had issue with first car, where I tried save money by replacing orings only. After that failed miserably, I bought whole set of tubings with orings mounted on them already and repeated on second car.
We keep the second car and after 3 years the engine is still bone dry.

 

[Plutoe]

How many bubbles have you counted, and are they contiguous say over lunch and have you ever estimated the bubble size distribution??? Or are the bubbles all the same size??

That effort would be good to estimate the amount of air in the system