The FBI is investigating a coast-to-coast "scam" involving con men posing as representatives of the Teamsters Central States Pension Fund and collecting "finders' fees" from would-be borrowers for spurious loan commitments, officials of the fund said.

George W. Lehr, executive director of the Chicago-based fund, said the scheme came to his attention last fall and that all information about it has been turned over to the Federal Bureau of Investigation.

Lehr declined to provide details, but other sources said the phony loan commitments total about $100 million and that the finders' fees that have been paid total hundreds of thousands of dollars.

"This is going to show some greedy corporations and greedy individuals," said one source close to the investigation. Major companies in at least six states are said to have been taken in. The "loan commitments" were for real estate and business loans.

The multibillion-dollar fund, subject of numerous federal investgations in the past few years of possible influence by organized crime families, is operating under a consent decree imposed by a federal court in Chicago.

Under that decree, Lehr said, "the fund's assets are managed independently by Morgan Stanley Group Inc., the New York investment banking firm. Neither Morgan Stanley nor any asset manager in its employ has issued any 'loan commitments' of any kind involving the fund's assets."

Lehr said the fund is making no new real estate loans now and is on the verge of shedding the last of its controversial Las Vegas casino investments, the Aladdin hotel and casino. It is being purchased by a Japanese firm.

"We will be out of the gambling and casino business 100 percent by the end of the month," Lehr said. He took over as executive director in October 1981.

Five reputed Midwestern organized crime leaders are awaiting sentencing in Kansas City for skimming almost $2 million in gambling receipts from a string of Las Vegas casinos financed by fund trustees in the early 1970s.

Pension fund spokesman Mike Kelley said the FBI would have preferred no disclosure of the fake-loan investigation, but he said, "we have to react quickly to these things . . . . We don't want to be victimized, and we don't want people victimized in our name."

Sources said three FBI offices are involved in the inquiry, but it centers on payments of fees to "two or three big players," apparently working out of one location in the West.

Lehr said, "We would advise any would-be borrower who may be the victim of this scam to get in touch with federal or local authorities."