Chrysler Corp. survived another brush with financial collapse yesterday by winning $622 million in wage and other concessions from United Auto Workers negotiators and a conditional promise of $400 million in federal loan guarantees, the key elements in a new financing plan to keep the automaker in business.

The agreements reached yesterday must still be approved by workers, suppliers and creditors before Chrysler can obtain the critically needed $400 million. The new Agreements are part of a package that Treasury Secretary G. William Miller said will "ensure" Chrysler's profitability in the future, but many industry experts are still skeptical.

UAW President Douglas A. Fraser called it "the worst economic settlement that we've ever made, and the only thing that is worse is the alternative. And the alternative is having no jobs for the Chrysler workers."

Given that choice, he said, the union leadership would recommend approval of the plan by the 64,000 active and 40,000 laid-off Chrysler workers in the United States and Canada. He said he wasn't sure what their reaction would be.

Miller, however, appeared determined to get the government's Chrysler loan guarantee board on record as supporting a new loan installment before the Carter administration leaves office Tuesday. Chrysler Chairman Lee A. Iacocca called the plan "a super deal."

After a day and a half of frantic negotiations, the loan board, headed by Miller, tentatively approved the new financing plan, which also requires Chrysler to obtain at least $36 million in concessions by its suppliers, and to reduce the wages and benefits of non-union employes by $161 million.

During the year, Chrysler will pay about $150 million in cash to lenders, eliminating about half of its outstanding debt at 30 cents on the dollar, according to the board's plan. The lenders would receive preferred stock dollar-for-dollar for the remaining half.

The UAW concessions, if approved by Chrysler's UAW workers, will freeze wages and benefits at current levels and will eliminate further cost-of-living allowances after a final payment in march for the balance of the contract, which runs until September 1982.

Chrysler says it will run out of money within a month without the $400 million in federally guaranteed loans. It is no longer able to borrow without the guarantees.

Miller said the loan board will meet again Friday, giving Chrysler time to seek approval of the new plan from its board of directors. The loan board expects to grant conditional approval of the financing plan Friday, with final approval expected early in February, Miller added, assuming that the union, Chrysler's 125 lenders and its suppliers all fall in line, and that Congress does not object to the arrangements.

As Miller put it, "some of the aspects . . . need to be buttoned up."

The new financing concessions would eliminate about $1 billion in Chrysler debt, significantly improving the company's balance sheet and increasing the company's prospects of joining with another, stronger auto company.

Such a merger offers Chrysler's only hope of long-term survival, Miller said, and, at his insistence, Chrysler has established a top-level committee and has hired consultants to speed up the search for new partners.

The concessions would save Chrysler about $783 million in wages and benefits, at least $36 million in concessions by suppliers, and twice that if Chrysler can get suppliers to go along, plus interest savings of at least $100 million. Chrysler also expects to cut its costs by $500 million this year by cutting back on advance work on future car models and components.

In the year since Chrysler first appealed to Congress for financial aid, the UAW leadership has agreed to more than $1 billion in wage and benefit concessions, counting the latest contribution. Wage and benefits for Chrysler workers now average $17.31 an hour, and a year-long wage freeze would leave these workers about $3 an hour below the contract figure.

"The whole plan is a billion and a half to $2 billion," Iacocca said. "we think we're going to be in good shape." The $400 million will be used to "get current" with Chrysler's suppliers, who are currently owed about $200 million by the auto company, and provide working capital for the weeks and months ahead.

Under the terms set by Congress when it approved $1.5 billion in loan guarantees for Chrysler a year ago, the loan board cannot authorize guarantees unless it is convinced that Chrysler can return to profitability by the end of 1983 and begin repaying the borrowed funds.

With the continuing slump into auto sales, Chrysler's future has looked increasingly questionable. Chrysler suffered an estimated loss of $1.8 billion in 1980, and has had to trim prices on its new K-car line by more than $500 per car to boost sales, cutting into its future profits.

Fraser said that, to balance the concessions, the UAW would have to get a profit-sharing agreement from Chrysler, and Miller said Chrysler and the UAW have agreed to continue negotiations on this point.