Federal energy regulators, looking past the immediate gasoline shortage, are passing the word that many Americans soon may face a dilemma that might be stated, in simplest terms: drive now, freeze later.

If the oil industry produces enough gasoline now to eliminate gas lines, the regulators say, it probably will not be able to produce large enough stocks of fuel oil to fire the furnaces of the nation's 16 million oil-heated homes next winter.

And even if adequate supplies of fuel oil can be produced by the start of the winter heating season, according to government and industry analysts, the fuel bill for the average home that heats with oil will increase from last year's level, about $90 per winter month, to as much as $180.

The choice between parked cars now and cold homes later might be avoided if supplies of crude oil, the raw material for both gasoline and heating fuel, increase quickly, or if the current demand for gasoline and other oil products decreases.

But if there is no sign of change in supply or demand within the next two weeks, the Department of Energy has concluded that it will have to take steps that will exacerbate the current shortages in order to provide sufficient reserves of heating oil by the start of cold weather.

Douglas Robinson, the second-ranking official in DOE's regulatory office, said the government wants refiners to reduce from 23 to 21.5 percent the proportion of each barrel of crude oil that is used for gasoline production.

That would reduce gas stocks by about 5 percent. Gas supplies are already between 10 and 25 percent below last year's level, depending on whose estimates one accepts.

Robinson added, though, that oil companies might fight such an order in court, and it is not settled whether the government has legal authority to issue such production orders.

In a pessimistic memo to the White House two weeks ago, the DOE suggested other steps that might be necessary to shore up heating oil stocks, including:

Reducing oil supplies to electric utilities this summer, thus impairing their ability to supply power for air conditioning.

Lifting air pollution controls so that some oil users can burn dirtier grades of oil, leaving more nonpolluting stocks free for home heating use.

Ending current rules giving agricultural users the right to all the fuel they ask for.

The potential heating oil crunch, like other oil-problems facing the nation, stems primarily from a shortage of imported crude oil. But the supply problem has been worsened by seasonal variations in the production and consumption of the various refined products.

In normal winter months, refiners increase the share of heating oil they produce from each barrel of crude. Since the first half of last winter was mild, though, the firms produced more gasoline than normal and less heating oil. When harsh cold swept in late in the season, consumers used up almost all of the existing heating oil stock.

This spring and summer, when producers would normally begin replenishing heating oil reserves, they slighted heating oil to meet increased demand for gasoline.

Robinson said yesterday that the industry will have to produce 7 million gallons of heating oil per week to build up the needed reserve of 240 million gallons by Oct. 1. In the first week in June, however, refiners turned out less than half the amount needed, and some of that heating oil went to utilities which burn the fuel in auxiliary generating plants they use to meet heightened summer demand for electricity.

When it comes time to choose between the production of gasoline to meet current drivers' demands and production of heating oil for the future, all government officials seem to agree that heating oil must take priority.

But the need to make a choice poses a political problem for the Carter administration. It can either earn the enmity of motorists by cutting gasoline production in summer vacation season or risk the fury of homeowners who cannot get enough heating oil in the chill of winter.