DETROIT — The Ford Motor Company on Monday posted a surprise third-quarter profit of $997 million and said it had its first profitable quarter in North America in more than four years.

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The carmaker also said it increased its cash reserves by $2.8 billion during the quarter, ending September with $23.8 billion.

For all of 2009, Ford, the only Detroit automaker to avoid bankruptcy this year, has had a profit of more than $1.8 billion. It reported $834 million of income in the first half of the year.

Its goal has been to break even or earn a full-year profit by 2011. On Monday the company said in a statement that it “now expects to be solidly profitable in 2011, excluding special items, with positive operating-related cash...