I've got astra G year 2000 17DTI and lately it's giving me problems. Last weekend started car normally and after a 15 minute drive I tried to restart car and no cranking from starter motor. All dashboard lights worked normally. I tried to start engine the next day and everything was ok. Took car to mechanic and he found no problem. Took car home again and problem resurfaced. Left car in garage for another day and car started but starter motor sounded weak, so I took car to mechanic again and we changed the battery (Car radio lost memory!). Drove back home and tried to restart engine and again no cranking from starter motor (the car had a new battery). Today I tried to start engine and everything was ok - even the torque of the starter motor felt normal. Could someone give me an idea of what the problem could be?