Here are Nissan Sentra engine problems, by model year. The most common Sentra engine problems cost $1,700 to fix & occur at 71,000 miles. Regarding the worst model year 2005 Nissan Sentra engine problems, "The 2005 Sentra earned its clunker status after numerous reports of blown head gaskets" Click on a year below.

Worst Engine Problems
blown head gasket 2005 Nissan Sentra
piston slap/ knocking 2010 Nissan Sentra
blown head gasket 2004 Nissan Sentra