U.S. automakers are scrambling for other ways to advertise their 1983 models after their fall television campaign was thrown for a loss by the National Football League strike.

NFL games have been the best thing going for TV introduction of new-car lines. The audiences are mostly male and largely affluent -- a dream crowd for auto advertisers.

The automakers already were in their season of discontent when the NFL players walked out six weeks ago. Sales had fallen to their lowest level in 20 years. But they were pinning their hopes for a recovery on an improved economy and the sleeker 1983 models with zippier engines. Now more than ever, they needed the kind of exposure afforded by the NFL games, the automakers said.

"Nothing is comparable for exposure," said media expert Richard Spaulding, commenting on the lost NFL advertising. "It's almost impossible to replace what you lose when you lose that."

Spaulding works for D'Arcy McManus Masius Worldwide, an advertising agency in Bloomfield Hills, Mich., that represents the Cadillac and Pontiac divisions of General Motors Corp. The two divisions had planned to spend $10 million on NFL advertising this year.

NFL games attract "upscale adults, 25 years to 45 years" in age, "with household incomes of $35,000 to $45,000," said Richard Welday, Cadillac's director of merchandising.

"The demographics of NFL football are pretty impressive," said Welday, who added that his division has been "reinvesting" its NFL advertising money in national newspapers and magazines in an attempt to hit its target audience. "As far as the breadth of the audience we're trying to reach, we're losing some exposure. As far as the depth is concerned, we're doing okay" with the alternate strategy, Welday said.

The whole mess has left car companies and their advertisers trying to figure out how to avoid similar disasters in the future. "Maybe we ought to wear helmets" in dealing with the networks, Welday said in jest.

But he said that the car companies probably could not protect themselves from being locked in early on TV advertising commitments so long as pro football is popular. That largely is the reason the companies have had to wait until each game is canceled to claim their unused NFL dollars, said Welday, whose Cadillac division had bought time in 14 games.

"We tried to get out of the weekly release this year," Welday said. But the division could have found itself in an advertising lurch if the games had resumed and someone else bought the remaining spots, he said. "The property we're talking about is very worthwhile, and the networks know that," Welday said.

The Cadillac division, like other divisions of other car companies, can reclaim its NFL television dollars on a weekly basis. The companies also can use their NFL "buys" as credits to buy time on alternate network programs with audiences having demographics similar to the NFL crowd. The problem is that those audiences, with their 60 percent male presence, are hard to find, the auto advertisers say.

"Prime time television," with shows like "Dallas" (CBS), "skews more toward women than men," said Bill Tenebruso of New York-based Kenyon & Eckhardt, the agency representing Chrysler Corp. Women generally are paid less than men and, as a result, are not as able to buy big-ticket items such as cars, he said.

Tenebruso said Chrysler and other automakers are "well aware that women are becoming a major factor" in car buying. But he said their clout usually is felt at the low end of the market. The "high-ender," the person who is going to buy the Chrysler LeBaron, for example, usually is a man, Tenebruso said.

"If men are important to you as buyers, you have to advertise where they are," and that's most likely in front of a television, watching an NFL game, Tenebruso said. He said Chrysler has diverted some of its planned $15 million in NFL spending, but has had only modest success in finding a pro-football-type audience.

"Our first alternative was to divert most of our money into the Canadian football replacement games on NBC. But Canadian football did poorly. So, we pulled out of that," Tenebruso said.

Over at Ford Motor Co., the advertisers had what turned out to be a better idea. Ford paid an estimated $1.1 million per game to be the only auto sponsor of the 1982 World Series. As a result, "we haven't really been hurt that badly" by the NFL strike in terms of exposure, said Robert Gillooly, national advertising director of the company's Ford division (the other division is Lincoln-Mercury).

Ford also was in a better position because its newest cars -- the radically redesigned Thunderbird and the all-new Tempo and Topaz -- start rolling into showrooms in January and in the spring. The staggered-introduction strategy is designed to keep up "year-round excitement over Ford products," another Ford marketing official said.

What remains to be seen is whether the NFL, whenever it resumes its games, can generate the same audience and excitement it had in the past. Auto advertisers, burned by current events, say they will pay close attention to any changes.

"We know a day or so after it airs how many people watched a given game," said D'Arcy's Spaulding, adding that the "NFL was virtually all of Cadillac's TV plan" for the first part of the 1983 model year that began in mid-September.

"We lost a major part of our audience," Spaulding said. "When and if the season comes back, we'll take a look at stadium attendance and TV ratings to see if the NFL has lost its punch."