RepairPal Certified shops can diagnose and repair your 1999 Cadillac DeVille. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
372,834 miles on my '95 Camry , NO smoke , no blown/cracked head yet!! Unless there is a DEFECT , or other known fault to CAUSE it , I don't consider any mileage 'normal' for headgasket or block issues.