that bit that confuses me is if its a ring or valve stem seals surely it would be there permanently but it intermitently comes and goes as it feels like it. Ive got a compression kit on route to test the rings. does anyone know what psi the chambers should be at on a 1.8t aum? also can i use the same kit to test the valve stem seals or is it a case of
one piston down on compression = rings on said piston
all pistons down on compression = valve stem seals/rings on all pistons
compression fine across the board = turbo
or am i just thinkin complete bollocks lol

if none of the above is correct how can i check the valve stem seals without removing the head and what not?