I have a 2015 VW Tiguan 2.0 TDI, DSG box. I have just had the 30000 mile service which is oil & filter, driven home from the garage about 3/4 mile and dipped the oil to find that it is black. Spoke to the garage who told me that this is normal for a diesel as the oil removes carbons from the engine as it runs. I am not 100% satisfied with this as I think it unlikely that the oil would discolour after such a short journey. Can anyone comment either way on wether or not I am being misled?

  • The old, "my mechanic is lying to me"... never gets old.
    – cory
    Jun 14, 2017 at 20:31

1 Answer 1


I don't have experience with diesel engines, but something doesn't seem right to me. A couple of thoughts are: 1) buy a quart of diesel engine oil at an auto parts store, pour some in a clear container, and see what color it is; 2) send a sample of oil from your engine to an oil analysis service; 3) look around underneath the car and see if it looks obvious that you have a new oil filter.

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