Exhaust Smoke - 'Check Valve' querey 1999 model 2.0 ecopower

[lightserv2]

I have cleand out the ventilation nipple on the crank case cover with a 2mm drill bit and found it was blocked. This I hope will cure the blue smoke I see on start up!

I also checked the code number for the 'check valve' and found it to be 9189564. On the site www.saabs.info, they say the check valve code should be 9399973. Which part number is right?

I have also looked at the modifications panel and it has the number 8 scratched in panels B5 & C4. I know what B5 is, but what was C4 modification?

Any info will be most welcome as I do not want to have the turbo pulled apart just yet if need be!!!!