Israel's negotiators in the Middle East peace talks yesterday gave Secretary of State Cyrus R. Vance a list of proposed changes in the draft peace treaty with Egypt, thereby raising fresh doubts about when the accord will be completed.

Although Foreign Minister Moshe Dayan refused to discuss what he told Vance, reliable sources said the chief Israeli demand was for further weakening of language linking an Egyptian-Israeli peace to future negotiations on the status of the Israeli-occupied West Bank of the Jordan River.

These sources said Dayan's fellow chief negotiator, Defense Minister Ezer Weizman, brought back from Jerusalem a request from the Israeli cabinet to delete the so-called linkage language from the preamble of the treaty text.

That request, initiated by hardliners in Prime Minister Menachem Begin's cabinet, would eliminate from the treaty text any reference to the West Brank and its Palestinian inhabitants. Instead, the sources said, Israel now has offered to refer to the West Bank question in an exchange of separate letters accompanying the treaty.

However, the latest Israeli bid to weaken the linkage language runs directly counter to Egypt's insistence that the treaty contain a strong and specific reference to the need to resolve the problem of the Palestinians on the West Bank and in the Gaza Strip.

In Cairo, Egyptian Prime Minister Mustapha Khalil was quoted as saying that Egypt's negotiators had "very clear instructions . . . that a separate peace agreement can never be signed ignoring the legal position of the Palestinians, especially in the West Bank and Gaza Strip."

Whether the new Israeli position on linkage will cause a setback in the negotiations won't becom clear until Vance hears from Egyptian acting Foreign Minister Boutrous Ghali, the sources said. Ghali, who had been in Cairo for consultantions, was expected back in Washington last night.

However, the reemergence of the West Bank linkage issue - the major sticking point in the month-old talks - appeared, at the very least, to dash hopes that the peace accord will be wrapped up within the next few days.

Last Friday, Vance said the major substantive issues had been resolved; some sources connected with the talks had made optimistic predictions that the treaty would be ready for initialing by this weekend.

Another point continuing to cause difficulties, the sources said yesterday, involves Israel's request for U.S. financial aid to help defray the costs of withdrawing and relocating Israeli military installations and civilians settlers from the Sinai penisula after the peace treaty goes into effect.

Despite Israeli denials, there have been persistent hints that the Begin government wnats to delay agreement on the treaty until Israel has a firm U.S. commitment on aid. However, the Carter administration is understood to be resisting strongly Israeli presures for a commitment on specific dollar figures at this time.

The possibility that the talks might be in for further delays was reinforced by Dayan's taciturn attitude after he emerged from his meeting with Vance. In contrast to his usual habit of giving reporters his views on the progress of the negotiations, he said: "I really have nothing to say this morning. Absolutely."

Later, George Sherman, a State Department officer serving as spokesman for the U.S. mediated talks, said: "After almost one month of negotiations, I think it's clear we're at the harder issues."

Sherman also confirmed that the negotiators are still struggling with another sticky issue - that of Israel's access to oil from Sinai fields after the area reverts to Egyptian control.

Egypt wants compensation from Israel for oil taken from the fields during the years of Israeli occupation. Israel, on the other hand, wants to be compensated for its investment in developing the Sinai fields and also seeks a guaranteed future supply of Sinai oil at preferential prices.