Sounds like you may have a split hose between the turbo and the inlet manifold.

Today i decided to do some fault finding under the roof of a gas station despite the rain and thunderstorm, and what i found was a small hole in the otherwise solid plastic of the part where HP air form the intercooler enters the engine, or the plastic rail connected to the engine. Im not sure what the proper name of that part is but anyway, its leaking a small amound of air from the hole when idling. I found it by plugging the inlet tube to the air filter box with a paper ball, then the hole sucks air and makes some well hearable noise that i could eventually track to that little hole. I really dont understand how that hole could appear, while driving, or thats when i first heard the noise of leaking air under load anyway, and i really think that is the source of the noise and also the reason for the engine light coming on with error code *P0100 Powertrain - Mass or Volume air flow circuit*

I suppose i should go ahead and plug that hole, but i thought id just share here first, and maybe get some feedback. Also on how to best plug it. Silicone? Epoxy glue? Plastic "metal"? Plastic glue that bonds to the plastic?

And should i leave the rough edges that makes it appears like an outward bullet hole (how the heck did that happen), maybe those gives whatever glue a bigger area to work on and a better grip to the otherwise smooth surface?

Below are 2 videos documenting the madness and showing the hole.

Combo C 1.3 cdti small air leaking hole in plastic part where air from turbo enters engine

https://youtu.be/TTrtG_b-r2E

Combo C 1.3 cdti small air leaking hole in plastic part where air from turbo enters - air leak test

https://youtu.be/YY-KlL-7EVw

images of the hole

https://ibb.co/D8SDBqS

https://ibb.co/ZXZW8xL

https://ibb.co/dbRHPN1

Its larger than 1, its probably about 3mm.

Yes it gets quite hot and the pressure air inside the manifold seems to make its way trough several attempts using polyuretane glue.

www.biltema.no/en-no/construction/chemicals/other-...6

The result looks good and feels solid until I drive, as soon as the turbo builds some pressure, woosh and its a small hole in the glue. It sounds like a lot of air escaping. The MAF lamp didnt come back on, so may be a but less than before, but no way sealed.

Superglue yes possibly. I was thinking of this plastic weld stuff (chemical, not heat)

plastidip.online/produkt/plastic-weld-syringe/

Or possibly heat is the best, I tried igniting a PEX fresh water tube, but access is hard so the dripping hot plastic would not hit the hole but 2cm a above it and run down, so itd be a lot colder by the time it reached the hole. And quite messy to clean up if it doesent get right the first time, or if it just doesent work.

PU glue is a bit easier to clean up using screwdriver & knife .. I think the JB plastic-weld may be the next thing to try? I got the feeling its better than superglue, thats so thin flowing and very brittle when settled in my exp.

then there is real plastic welding, but access is not the best, and i cant get the air supply hose from the filter box out of the way because the bolts wont come out, so id have to break the plastic fasteners for it and so on. Also im not sure what kind of plastic filler to add. My best guess is that its PVC, and maybe i could add a piece of a plastic waste water pipe of pvc.

Its possible i can find a breaker who lets me take the manifold off a car but disassembly and assembly seems like a not fun job. Its attached to the EGR in god knows what way, and the videos i could find were for gasoline engine. I need to search for a more relevant video to see what im dealing with in that possible solution. That would probably be the best fix but not the easiest if there is a glue that can hold the pressure (i would think there is and that i just tried the wrong one)

Thank you for replying and any suggestions extremely welcome!! :)