TL*THE CONTACT OWNS A 2006 SAAB 9-3. THE CONTACT STATED THAT EVERY FOUR MONTHS AND APPROXIMATELY 30 MILES, THE COOLANT RESERVOIR CRACKS, WHICH CAUSES LEAKAGE ONTO THE ENGINE. AS A RESULT, A FIRE ERUPTS UNDER THE HOOD. THE FAILURE WAS NOTICED WHILE DRIVING 30 MPH. THE CURRENT MILEAGE WAS 12,500 AND FAILURE MILEAGE WAS 4,000.