Question: what is a 1.6 hdi engine?
Answer: 1.4 HDI ( 20,000 Miles or 2 Years) 1.6 HDI (12,000 Miles or 2 Years) It has been evident in my experience that these recommendations are way too far apart. These Engines run extremely hot which in the long term effects the chemical structure of the oil causing it to thicken and congeal.