Saab 9-5 2.3 LPT 2002, 86,000 miles, white smoke on start up

[QBee]

White/light grey smoke suddenly on start up, accompanied by a metallic noise like small metal blades catching.
Have I elected a new Pope, or has something gone wrong?
If so, what, please?

More history - bought it 4 weeks ago, knowing it was due a service.
Oil warning light flickered on being stuck in London traffic on the way home, otherwise fine.
Oil and filter changed, sump dropped and cleaned the next day.
No more oil light.

Next issue was a water leak - identified as a leaking heater control valve - valve changed.

1000 miles into my ownership, drove 180 miles of main roads, no problem, then had a half mile/5 minute queue to a roundabout.
Soon after that, the temperature gauge went to the top of the scale and the red triangle warning appeared on the dash.
Car not boiling, I allowed it to cool down and set off again. Temperature fluctuating up and down for the remaining 10 miles to home.
Took it to the garage the next day, they tested everything, including the thermostat and water pump, which they took off to test.
Their pressure tests and so on suggested it wasn't head gasket, and they eventually found the heater matrix and radiator were both clogged with RadWeld or similar. All cleaned out, left running on test for several hours, all fine.

25 miles later, I noticed a tiny whisp of smoke on start up.
4 miles and three hours later, big clouds of white smoke on start up, plus a metallic catching noise from under the bonnet.
Looked under bonnet but couldn't see where the noise was coming from.
Stopped engine, restarted it, more smoke.

Questions:

1. What do you think the problem is?
2. If by any chance it is a failed turbo, can I swap in a turbo from a later 9-5 Aero I have redundant on my drive way? The Aero is a B235 engine, the 2.3 LPT is a B205 I think.
3. What's going to go wrong next?

[Stiggolas]

The 2.3 lpt is still a B235 engine, the 205 is the 2 litre. The turbo should be a straight swop but you might need a remap to get the best out of it. My lpt was running 235bhp from a stage 1 map, with that turbo you should be looking at 250 plus

[eybic]

White smoke is generally water whereas blue is oil. Do you get any kind of misfire on initial startup if it's been left overnight? I had a Nova years ago that to all intents and purposes had no issue with the headgasket but it used to misfire on startup each morning, within a couple of thousand miles, the HG went.

[QBee]

Thanks guys - it turned out to be the turbo - broken bearing that caused blade damage.

My trusted mechanic said don't use the old one, buy new, so I called Neo Brothers.
Their trusted after market turbo was around the £200 mark, but they said I needed a fitting kit, new pipes etc and a new load of oil plus filter.
Two boxes full came to £367, but it was worth it because the car runs perfectly now.

Thanks for responding.

[Stiggolas]

Great to hear that your up and running again. I'd still look at a stage 1 remap from Karl (Noobtune). It will transform the mid range and for only £80 its a no brainer. He likes doing the LPTs 'cos you get the most increase for the remap

[Timmos1974]

Brilliant cars...

Never should of been stopped really.