THE CARTER ADMINISTRATION is now attempting to warn the public of a possible oil crisis, but without actually starting a panic. That will probably prove impossible. If Americans begin to take the warning seriously -- as they assuredly ought to -- some will inevitably react in ways that make matters worse. There's already evidence of a little hoarding here and a little profiteering there.

The administration itself is, as usual, adding to the confusion by the variety of its own pronouncements. Secretary of the Treasury W. Michael Blumenthal, who is worried about the day-to-day strength of the dollar, deplores the admonitions being delivered by Secretary of Energy James R. Schlesinger. But Mr. Schlesinger is right -- right, unfortunately, in his assessment of future oil imports, and right in his decision to talk about it openly.

The administration's job would be easier, in a sense, if it could say with certainty that a great wracking shortage of oil were coming. It could then swing into the high-powered response to crisis that is so congenial to the American spirit. But certainty is a luxury granted to no one who deals with oil and energy policy. If the administration blows the bugle and braces the country for an emergency that never arrives, or arrives only in a mild form, the costs in disruption would be exceedingly high. But to err on the Blumenthal side, by dismissing the possibility of a severe shortage until it actually developed, would be even more costly. The administration seems to be adopting, hesitantly, a step-by-step tactic of gradually raising the level of the warnings, in proportion to its changing assessments of the danger. By every indication, the chance of serious trouble soon -- by which we mean this spring -- has risen substantially in the past couple of weeks.

The structure of the shortage begins, of course, with the Iranian revolution. In late autumn, the turmoil in the oil industry there dropped exports to zero, taking nearly 6 million barrels of oil a day off the market. That is about one-tenth of total world production. But there was no immediate effect, because other Persian Gulf governments -- preponderantly Saudi Arabia -- raised their production to cover most of the Iranian shortfall. The Saudi production went up from around 7.5 million barrels a day during the summer to some 10.5 million by the year's end. But late last month the Saudis announced that production in the first quarter of this year would be held down to 9.5 million barrels a day. Currently, there are indications that their actual production may be considerably lower, perhaps no more than 8.5 million barrels. When Saudi exports decline, there is no other source capable of filling the gap.

One victim will probably be the administration's earlier intention of decontrolling crude oil and gasoline prices. A government can only lift controls when prices are not rising, and oil prices around the world are now beginning to move upward again. Because gasoline prices here are held artificially low, gasoline consumption has been climbing steadily higher and, in fact, oil stocks in this country are currently below normal. That is where the mechanism of panic will begin to operate.

The prospect of sharply higher prices ahead will induce companies, brokers, traders and retailers to try to build up their reserves, so that they will go into the shortage and worldwide price increase with their tanks brimming. With the big international oil companies already beginning to cut back on deliveries to their customers in Europe, the grab for remaining supplies will get more anxious. That, in turn, will aggravate the small but perceptible shortage that has now begun to appear. Which, in turn, will incite still larger increases in world oil prices.

Nobody really knows what the Saudis intend to do in the months ahead. No one can say how long it will be before Iran begins shipping oil again, or how much it will choose to produce. But it is rapidly becoming an urgent international responsibility to restrain the speculation and squabbling as markets tighten.

The Saudis, you might say, got their customers in America, Europe and Japan smoothly through the winter. Nobody froze. But it begins to look as though the passage through the coming summer vacation season is not going to be quite so smooth.