SAAB GM900 2.3 n/a smokey startup.

3 or 4 times in the last few weeks now I've come to start my car up and been engulfed in clouds of blue smoke. It lasts 15-20 seconds then disappears, it's usually fine, it only happens every now and again.

This has come on pretty quickly. There's been no leading up to it with it smoking slightly, it's pretty bleeding smokey ;(

I have no turbo so was guessing at knackered valve oil seals, after searching the SAAB forums I can't find any info where it doesn't end up being the PCV and/or turbo so I was wondering if it's a common problem on the SAAB 2.3 non-turbo engine ?

Anyone changed the oil seals on the SAAB engine, any suprises or caveats ?

Cheers in advance, Tony