[Tervuren]

Not enough detail from you to go on.

The original 2009 XF S(upercharged) was a 4.2L V8, I am not aware that they were unreliable.

2010 went to massively more powerful direct injected 5.0L V8 and also added a V6 engine option.

If well maintained, I am am not aware that they were unreliable.

The V6 S(upercharged) could also come in AWD.

2012 got a face lift in styling.

2013 got an eight speed gearbox.

2016 They dropped the V8 S(upercharged) from the XF line up.

Direct injection is relatively new for gasoline cars, it does introduce some problems.

Insure regular oil changes have been done, do regular oil changes.

These engines make finer soot particles than present oil specs and filters account for. Changing the oil gets rid of the build up.

Any used car is rolling the dice no matter how good it may be; hence the depreciation.