One problem related to manifold/header/muffler/tail pipe has been reported for the 2008 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Hyundai Sonata based on all problems reported for the 2008 Sonata.
On the 3. 3l engine there is a fault in the intake manifold gasket that causes oil to leak onto the alternator causing premature alternator failure. If the vehicle loses power while driving this can increase the risk of a crash. This problem has happened on other vehicles with this same engine such as the veracruz and a recall has been initiated. For some reason the recall does not extend to the Sonata as it should. The following is from the veracruz recall involving the same engine. "Hyundai motor company (Hyundai) is recalling certain model year 2007-2012 veracruz vehicles manufactured from December 26, 2006, through July 24, 2012. The affected vehicles may experience an oil leak from the front cylinder bank valve cover gasket. If there is a sufficient amount of oil dropped onto the alternator, the alternator will be damaged causing the charging system to become inoperative. " my alternator has failed twice now, once while driving and I experienced a total loss of vehicle power. I was able to force the vehicle to the side of the road without incident but it easily could have gone bad on me as I was on the freeway in traffic. Once my alternator and subsequently my battery died I was left without control of the vehicle and without lights on the vehicle to warn other drivers of my situations.