Meal, I am now for about 3 months and 10,000 km owner of an Omega B, 2.5l, 6 cylinder, diesel. The “seller”, probably an Opel-screw, told me that it is normal that the Omega takes relatively long to start. With increasing cold it took longer and longer – until he suddenly would never want to. Engine was after a short purchase still at operating temperature, battery diligently driven the starter, but engine did not ignite. Then yesterday again the same. I then clamped a starter car to the battery. As a result, the starter turned faster and the engine was perfectly started within a second. Now my thesis: Although, according to the manual, the installed 70 battery is correct, it can not be that I better install a 100 amp battery? The condition of the battery is good. Charging condition is also good. Best regards, the Oppa