According to Consumer Reports, which does not break out diesel from gas products, the Volvo XC60 from 2014 to 2017 has minor engine problems (e.g. issues like the water pump, power steering pump, secondary systems failing). In 2014 it is way below average (the worst rating) and in 2016 it is also below average. For some reason 2015 and 2017 are much better and no problems are reported. In 2017 it is rated below average in transmisison reliablity as it has problems such as rough shifting (it is rated under minor transmission problems).
Be aware, these cars for all four years overall are below average in reliablity to average as they do have an assortment of issues every year.
2014 - minor engine problems, paint and trim issues, body intergrity (creaks and rattles), and power equipment failures (overall average reliablity)
2015 - some drive system issues, climate control issues, premature break pads wearing out, body integrity, and the worst reliablity on power equipment and in car electronics (overall below average reliablity)
2016 - minor engine problems, electrical system issues (alternatory, battery, etc.), power equipment issues (average overall reliablity)
2017 - minot tranmisison issues, body hardware, in car electroincs (last one very poorly rated).
Volvos are nice to drive, but their reliablity in this model in particular is not very good for those years. For reliable smaller SUVs you have to go to in the luxury market to BMW X3, Porche Macon, Lexus NX, Audi Q5, and Buick Envision. The Volvo XC 60 and Infinti QX50 just are not as reliable. (all based on Consumer Reports)