oil leak turbo cold side
 

hi on my 2002 24v with a super b turbo. I had the boot after the turbo blow off and when it did I noticed oil in the general area of the tube. is this common to get some oil leak? the turbo has about 25000 miles on it. I have been noticing it's been losing about 2qts of oil per 10,000 miles. I was wondering where this oil was leaking. what would cause this leak?