Major oil loss. Now stuck where to look

[s40t]

Since doing my engine and running for a good months now, with the 15t I've noticed (very hard to miss) a massive amount of oil loss. I have checked all seals, none loosing any there, turbo return drain pipe is not loosing any, replaced vvt gasket as it was broke but still just as bad, no signs of runs anywhere which led me to believe a weak crank housing gasket to the engine possibly spraying but I really beg to differ. PCV seems good too. Your probably wondering how much is being lost. Well it's about 2-3 litres a WEEK. It doesn't smoke until gear change or overrun and it has travelled right the way under the back to fuel tank. Driveshaft is soak and so is the rack. I'm now thinking turbo oil seals but it's not burning oil from the exhaust just underneath. And whatever it's touching that's hot engines is dry too. Also this occurs under driven load not stationary revving. Any help people? Thanks

[Orca2]

Best bet is degrease and pressure wash the whole area off , let it dry and recheck to see where it is coming from.
My mate had a tiny diesel leak on his Vito Van , and we could not find it until we degreased the whole top of the engine , we very quickly found a slightly slack clip on the fuel pump, we ould never have found where it was coming from while the engine was all covered in diesel.

Ps the fact that it is leaking under load and not while it is running in neutral, sounds like it might be an oil feed pipe that is being strained when the engune is under load, check the oil lines to the turbo.

[960kg]

Have you checked the oil cooler?...a rectangular metal box which is situated under the crankshaft pulley end on the block......coolant goes to it via hoses and the "O" rings can go and leak oil from the sump.oil!

[s40t]

Have you checked the oil cooler?...a rectangular metal box which is situated under the crankshaft pulley end on the block......coolant goes to it via hoses and the "O" rings can go and leak oil from the sump.oil!

I did check that yeah and it was fine, didn't know about the O rings though? This I'm guessing is a job during oil and coolant change for practical matters. Can it be done with the cooler in place or are they right inside? No experience with oil coolers as you can tell. I don't personally think it is as I've noticed smoke from turbo area on over run. Maybe its worth a turbo rebuild