Car liability and comprehensive insurance for V70_3 much more expensive than for V70_1

Why is the car liability and comprehensive insurance for a V70_3 so much more expensive than for a V70_1? For my V70_1, EZ 06_1997, gasoline, 125 kW, I had to pay slightly rising over the years 1990 to 2017 approx. 210 to 260 € for HV, VKV, TKV. BUT: For my V70_3, EZ 6_2008 Diesel, 136 kW, the same company calculates for the same range of services HV, VKV, TKV a premium of 610 €. How is this difference justified? An insurance comparison at Verivox shows, that my Vers.Gesellschaft belongs to the most favorable. Other insurers are even more expensive. If V70_3 owners are more frequent accident causers, are V70_3 stolen more often, are diesel generally rated higher, is the V70_3 classified as expensive exotic model, or what are the transparent reasons? That a pensioner malus would be calculated to me, denies my Vers.Gesellschaft.