Can anyone help me please, this is doing my head in. I know that this subject has been covered on this forum many times and I have searched it for the answer but no luck. My Cossie 4x4 1990 has covered 115,000 kilometres (60,000 miles) from new, one previous owner (old guy), has horrible oil consumption, namely 1 litre every 1000 kilometres (2 pints for 600 miles). I have done the following :-

Compression check, 140 psi on all cylinders both hot or cold
Changed turbocharger from a vehicle that uses no oil at all.
Disconnected vacuum pipe from inlet manifold to engine breather.
No signs of oil in air filter, intercooler, throttle body etc.

Greyish blue smoke comes from exhaust when in boost although can be forced to smoke if gearing down in all gears (engine braking) and when nearly stopped engine revved and hey presto smoke. If I disconnect the pipe from throttle body to intercooler then smoke goes really blue and is more prominent. I should say that this is not plumes of smoke just light stuff. Now thinking piston rings or valve stem seals. Hard to think that it is rings as such good compression, low mileage, careful use etc. as it is a very genuine car. If it is oil control rings gummed up or worst still broken, then why no crankcase pressure up through breather.If I disconnect the pipe from air cleaner to breather and suck on it there is a resistance which sucks back at me when I stop, is this right. If top rings are good and oil control rings bad then how does the oil get past the compression rings. If it were valve stem seals then why doesn’t it smoke on cold start up.

Somebody help me before I push the damned thing off a cliff, if we had one, only mountains here in Canada