Marshall:
The Volvo had 150,000 miles on it when I got it (now has 220,000 or
so), and I believe the turbo was shot when I got it. Certainly the new
one is MUCH louder, unlike my Benz turbo.
The Benz was used, and was smoking when purchased, but being a W140 I
don't know if it had the trap or not.
Using non-synthetic oil is rough on turbos -- you MUST fully cool them
after driving or the oil cokes on the bearings eventually, and they die.
The seals can also fail with good bearings in place, like everything
else they do wear.
Probably the most common cause of failure, though, is Interstate
Highway rest stops -- pull a long grade at 80, pull in, shut the car
off, fry the turbo. I let mine idle a while any time I get off the
Interstate. Note that sitting at a stop light counts as idle time....
Chunks of ceramic matrix flying around in the turbine will shorten life
dramatically -- they chip the turbine blades and unbalance the turbo,
and the bearings go.
Peter
