Henry Ford II announced yesterday that Philip Caldwell will be the new president of Ford Motor Co., replacing Lee Iacocca who Chairman Ford personally fired in an abrupt ouster in July after 9 years in the job.

Caldwell, 58, is already vice chairman and deputy chief executive officer of the No. 2 automaker. He will keep those titles when he assumes the additional posts of president and chief operating officer of Ford on Oct. 16.

Caldwell, a 25-year veteran of the company and the former head of its highly successful European auto operations, was considered the favorite to get the president's job.

But the timing of yesterday's vote by the Ford board came as a surprise since Chairman Ford at a press conference only two days ago specifically said the question of a successor to Iacocca would not be on the agenda of yesterday's board meeting.

Company spokesman were at a loss to explain the change of plan. "Only H.F. II can tell you that, one said.

Caldwell will continue to be a member of the three-man office of the chief executive along with the chairman, and his brother, Willaim Clay Ford, who is considered most likely to to succeed Henry Ford II when he retires as chairman and chief executive officer of the family-controlled multi-billion dollar corporation in 1981.

Because Caldwell already has day-to-day operational responsibilities for running the company, news of his ascendancy to the presidency caused little surprise in Wall Street.

"His responsibilities haven't changed," commented Ronald Glantz, auto industry analyst with Paine Webber Mitchell Hutchins. "Caldwell was given a made-up title to put him ahead of Iacocca in the pecking order.Now he's being given a more normal title reflecting the job he's actually doing. It doesn't mean too much."

The only alternative speculation had been that Caldwell might continue as No. 2 man in the company, but that the presidency title would go to William Bourke. Ford executive vice president who is in charge of its North American operations.

Caldwell will get the presidency at a time of near-record profits for Ford, but also some major headaches, particularly with regard to its economy-sized Pinto.

Ford recently ordered a recall of 1.5 million Pintos built between 1971 and 1976 because of a hazardous fuel tank. And on Wednesday an Indiana grand jury charged the company with teckless homicide and criminal recklessness in connection with three women who died in Pinto crash lat month.

Caldwell's strengths are said to be the cool way he manages operations, and his style is in direct contrast to that of his flamboyant predecessor.

"He is not the outspoken hot personality that Iacocca was," said one company source. "He is conservative and doesn't talk a lot."

Those qualities may stand him in good stead since one of the explanations given for Iacocca's firing was his high profile in the auto industry in competition with the equally high visibility of the company chairman.

Caldwell joined Ford in 1953. He was appointed general manager for the company's North American truck operations in 1968, elected a vice president of the company the same year, and in April 1970 he was named president of the Philco-Ford unit of the company.

In another appointment, Ford announced yesterday that John McDougall, executive vice president of the operations staffs will become executive vice president in charge of operations for North America, reporting to Bourke.