All solved! Leaking was caused, because there was a tiny black piece of dry silicon close to the intake cam's front axel seal. I noticed that from my old photo now. I just took the cover off, and installed all normal way again - and no leak anymore. No idea where it had dropped there.

Is it really needed to align VVTs according to marks it has? As I see it, there is no need for that, if the cams are locked - as they are when VVT is loosened/installed.

The minor dot/mark is obviously used at factory process when assembling engine. The VVT works not depending on its position ...

In this 2,5 Turbo the seal does not touch cam, but only VVT and bliock+valvecover.

Yes, I am very familiar with different Volvo breathing system. This has all new there and has irmal, small vacuum - all ok there.

It has brand new entire breathing system - which works well.

Yeah, issue can be Victor Heinz seals, which I tried. Corteco could be more tight.

I tested different depth, but no difference. Used 3D printed, original design tools.

Yes, it has 330.000 km. I measured exhaust: 3,2 mm and intake 1,7 mm.
I replaced both.

Well - it was OK beforehand. Now I used a RTV silicon sealant outside the cam seal. Lets' see tomorrow when it will be dry, how it works.

Nice advices here: viewtopic.php?t=100439

This is very educating for VVT and its oil leak understanding purposes.

I have now struggled days with leak behind a new VVT-sprocket without success. Now I'll try to use RTV sealant on outer side of the axel seal. Hope that solves it.

I've got major problems to get Volvo B5254T2 motor's front cam seal properly installed. It leaks.

Does anyone have experience in using additional sealant to get seal's outer surface not leak?