Originally Posted by
aeromech3
Just a suggestion but the oil consumption run would be a way of determining this fault, of course running up to 4 engines at power can be impractical and costly so some idea from oil uplifts should narrow the field, older cold air units with oil sumps can produce this problem and the APU has to be eliminated but usually this smell occurs during take off and early climb out. Even the quad B744 will need an opposite balancing engine when power is applied.
Eng3 was already suspect due to it's higher oil consumption.
And the oil smell actually occured during descent and taxi in on the previous sector, which was a bit puzzling. Oil leakage is a known problem on the P&W 4000 series, and there are a number of SB's about oil leakage caused by carbon seal wear and coking.
The engine was subsequently replaced, so the complaint has been closed. It had been due for replacement at the end of the month anyway.