Audi 3.0 Turbo Engine found in the S5, S4, SQ5, A6, A7, etc. Audi B9. Replacing the oil filter housing. The part number for the housing is 06M 115 401 L. When diagnosing the oil leak, it appeared to be leaking out of the rear main seal. Oil was coming out of the back of the engine where the transmission is mated. After further inspection I could see that the valley-way was full of oil and the oil filter housing was drenched in oil. Audi oil leak repair.