Hi, blue smaoke at your exhaust at start and idling looks to me as oil
consumption.
At start the engine is cold so there is a lot of space between the parts of
your engine and when idling the becomes a vacuum inside wich sucks the oil
in.
For older cars this is completey normal and there might be oil sucked in
between the valves and their housing
There is a rubber cap closing the space between the valve and its housing,
its placed inside the valve spring so you have to remove all valves which is
quite a job :)
(if other native english speakers read this and your a car mechanic then you
know what I mean, so please explain further).
You can ask your local volvo garage about this and find out what it costs to
fix it or maybe a specialized company can fix it for you.
Good luck!

a proud 480 driver

Hi,

The two worst things it could be are the turbo and the rings.

To check the turbo, remove the hose that comes from the turbo and goes to
the intercooler. Check inside for the presence of oil. If it is oily the oil
can only be coming from the turbo so that could be pricey and may fail
suddenly. If it seems dry then the issue is most likely to be either the
piston rings are shot (but that tends to exhibit itself more as oil on
acceleration), worn valveguides or guide seals (tends to show as oil after
long period on idle or on overrun such as at teh botom of a hill when you
accelerate again).
High crankcase pressure (worn rings or blocked crankcase breather) can also
cause blue smoke.
As long as it isn't the turbo it is unlikely to fail suddenly so just keep
going!