Believe it or not, New York City again faces a serious cash crisis and could run out of money to pay its bills by Nov. 1.

Despite action by Congress in July to provide the city with $1.65 billion in long-term federal loan guarantees, legislation to allow the city pension funds to buy the large amount of guaranteed debt without violating fiduciary responsibilities has yet to be enacted into law and signed by the president.

And the entire $4.5 billion four-year financing package - including the guarantees - that is supposed to keep New York City solvent through fiscal 1982 is still far from complete, with the banks, unions, pension funds and the local, state and federal levels of government and their various watchdogs all wrangling over details. The document has now grown to nearly 300 pages.

Meanwhile, concern is monting that, despite the plan, the city faces the likelihood of sizable budget deficits in the next few years.

And the different parties to the plan are "all trying to jockey some financial leverage at that time in case that happens," said Felix Rohatyn, chairman of the Municipal Assistance Corp. "Everybody wants an 'atomic bomb' clause. They want to protect their own interests."

MAC is a state agency created to finance city debt.

Rohatyn, architect of the rescue package, yesterday summoned all of the interested parties to a special Columbus Day negotiating session at his office at the Lazard Freres investment banking firm where he remains a partner.

"Someone asked if I wanted a Camp David summit," said Rohatyn. "But I told them that, with this cast of characters, I would prefer the Bronx Zoo." In a more serious vein, Rohatyn said his intent was to "keep grinding this out" until an agreement is reached.

The MAC chairman said that, as in the past, "Things will come together when the city runs out of money."

There is some dispute as to when exactly that will be.

Paul O'Brien, a deputy to city Comptroller Harrison Goldin, said yesterday that the city has been battling cash-flow problems for weeks, but "the date when we absolutely run out of cash and can't do anything about it is Nov. 1."

But Rohatyn, noting the numerous times when the city has cited a looming deadline for insolvency only to scrape up some short-term cash until a new financial plan can be negotiated, said "my definition of infinity is the day New York City runs out of money."

"But it will run out of money some day," he added, "and then there will be a disgraceful rush to complete this at 5 minutes to midnight."

Several weeks ago, Mayor Edward Koch imposed a freeze on city hiring and promotions to fight the reborn budget crisis. The failure to receive expected federal revenue had created an immediate $60 million budget gap. And Deputy Mayor for Finance Philip Toia said that the city may face a $500 million budget gap in fiscal 1980.

Ten days ago, the city had to receive help from the state legislature in Albany to meet a $230 million city payroll.

Since June 30, when the previous federal short-term loan program expired, the only borrowing the city has done involves the sale of $108 million in city debt to the police pension fund - a takedown that was delayed for two months until August because wage negotiations between the city and the police union were taking place.

The city today would not be facing a cash crisis if the various parties could agree to the $4.5 billion financial package. But there seem to be a number of sticking points:

The federal government wants its guarantees to be limited to 13 years for any borrowing done in fiscal 1981, instead of the 15 years contained in the legislation. The city would like to retain 15-year guarantees for all the $1.65 billion in order to keep its debt service payments as low as possible.

The banks are concerned that the state's Emergency Financial Control Board, which keeps tabs on the city's progress, either could be watered down or by the legislature or ruled unconstitutional by the courts. They want a clause to accelerate payment of the city bonds they hold in case this occurs. This immediately would put the city into bankruptcy, and is therefore unacceptable to the city.But the banks think that, whit such an onerbus condition in place, the state legislature or courts think twice before changing the authority of the EFCB.

The unions want assurance of continued levels of federal aid in future years to make sure the plan does not become unhinged because of reduced assistance from Washington that would necessitate further budget cuts and probable further layoffs.

The question of federal aid levels to the city is at the heart of concerns that all the parties seem to have that the city faces serious ballooning budget deficits in spite of the plan.