My 850Turbo was leaking oil from the oil cap, so I replaced the oil cap gasket but it still leaks(not too much). I also noticed that there is a small oil leak on the bottom side of my turbo...it looks like it is leaking around the hose that goes to the intercooler. Now I read an earlier post that said that an oil leak there is normal. I also smell oil outside the car after driving it. I also got a fault code for my front o2 sensor. Can all these be related? Could oil be contaminating the exhaust to make the o2 sensor fail? Also, could my oil leaks be from high crankcase
pressure? If so, is there any maintenance that can be done on the crankcase vent. sys.? From what I've seen and read, the vent. systems on these cars are pretty complicated.

Thanks,
Chris

Probaly your turbo oil return pipe seal leaking. The intercooler has a bleed hole on the bottom to let excess oil leak out. Excessive oil leak from turbo is possible and can damage 02 sensor but if that bad you should see blue smoke out of tailpipe.