In 10 years as secretary general of the United Nations, Kurt Waldheim has been faced with a multitude of international crises and, by his own admission, hasn't solved very many. The opening here today of the 36th annual session of the U.N. General Assembly finds the tall, gaunt Austrian diplomat with a few new problems, a lot of old familiar ones and a feeling of frustration that people expect him to come up with too many answers.

He is expected, among other things, he says, to "solve the North-South problems, get the Soviets out of Afghanistan, and get the South Africans out of Angola. Impossible."

That isn't the half of it. Among the items the General Assembly will deal with in this 13-week session are longstanding conflicts which, like comfortable old shoes, turn up year after year on the agenda, inviting the same old debates that many of the old-timers here could recite in their sleep.

These issues include Cyprus, variations on a dozen Mideast themes, who runs the world's information systems, who controls its economy, who should have nuclear weapons and who should start getting rid of the weapons it has, energy, human rights, who owns the seas and who controls the heavens.

Cambodia, and the Vietnamese occupation thereof, is making its third annual appearance as an agenda item this year. Third World countries are asking for greater representation on the Security Council, and the Americans are asking for a hearing on alleged Soviet use of biological warfare.

On the relatively short list of good news items, Belize, scheduled for independence from Britain next week, is likely to change its place on the agenda from "decolonization" to "new members."

"In my view," said outgoing 35th session president Rudiger von Wechmar, a longtime West German diplomat, the current General Assembly will be "one of frustration, of possible confrontation in a number of cases," and will likely end up with "a large stock of unsolved problems."

Waldheim maintains that he is not discouraged. In the first place, despite popular perceptions of his role and power in this country and among other U.N. members, direct problem-solving is not his job. The General Assembly, the Security Council and the dozens of other sub-agencies that make up the U.N. system -- the member countries themselves -- are the ones that are supposed to solve the problems. He is merely a facilitator, a "good office," designated as the public face of the international organization.

And even if the member countries come to few conclusions or solutions to what divides them, at least, as many people who walk these halls will tell you, they are talking here rather than shooting.

"We make our contribution," Waldheim says, "by talking to each other."

The talking -- the endless debates that are begun and ended with suffocating mounds ofpaperwork that everybody complains about and seldom reads -- is one of the things that most upsets the United States about today's United Nations. The problem is that a lot of other countries are doing it louder than the United States, and much of it is directed against Washington.

In her first few months in office, U.S. Ambassador Jeane Kirkpatrick was heard frequently to disparage the United Nations as a relatively useless forum, where rhetoric reigned and little of substance was accomplished.

It is not an uncommon view in the United States, where Americans have grown tired of paying the largest individual share of the United Nations' expenses -- nearly $500 million in 1979 -- only to hear their values and government branded with such terms as "imperialist" and "capitalist."

The European allies, who consider themselves much more worldly in matters of Third World diplomacy, are sympathetic. They, according to British Deputy Ambassador Hamilton Whyte, understand that things have changed in the United Nations, changed "to an extent still not realized by North America."

To a collection of American reporters here on a pre-Assembly tour, Whyte explained that in the beginning, when the United Nations first met in 1945, there were 51 member countries, most of them in Western Europe and Latin America. From Africa there were three: Egypt, Ethiopia under Haile Selassie, and "that curious sort of neo-American colony," Liberia. A few Asians were included, and a small "opposition" consisting of the Soviet Union and three Eastern European allies: Czechoslovakia, Poland and Yugoslavia.

The West "had a built-in two-thirds majority," Whyte said. "It was essentially a Western organization, and the Third World barely existed."

The issue was the Cold War, and the goal international peace and security. In the grand Security Council debates that kept Americans glued to their television sets, the Soviet Union pounded the table and found the only way it could succeed was to use its veto since, as Whyte points out: "They didn't have the votes."

Today, there are 155 members in the United Nations, the result of massive world decolonization that has given the Africans and Asians the two-thirds majority the West once had. As a result, the United Nations today is a totally different organization.

The definition of international peace and security for the majority has changed. For the Arab states, it is the problem of the Palestinians, the status of Jerusalem, the problem of Middle Eastern refugees. For the Asians, it is Cambodia, the Vietnamese invasion, the threat to Thailand, the occupation of Afghanistan. For the Africans it is the ongoing problems of white majority rule in southern Africa and for the Third World as a whole, East-West is not half so important as North-South.

Both the United States and the Soviets have lost out in terms of directing the attention of the organization. For most of the Third World, Whyte said, verbally "bashing the Russians is old hat, boring and unproductive. On the Russian side, saying that all the world's problems are a result of Western neo-colonialism is equally boring."

Still, as Kirkpatrick found and graciously said in public after the United States managed to work out a deal here that allowed it to condemn Israel in the Security Council for the raid on Iraq's nuclear reactor without too far alienating Tel Aviv, the United Nations does have its uses.

It also has its relative success stories, such as peacekeeping forces in the Middle East, Cyprus, Kashmir, the Dominican Republic and otherareas, and the establishment of international standards -- despite the degree to which member states may implement them or not -- in human, civil, economic, social and cultural rights. International agencies have been established that have eradicated diseases, housed and fed the homeless, and paid for development programs.

And for Waldheim, it cannot have been too bad, all in all. The secretary general has announced his candidacy for an unprecedented third term in office.