Responding to requests from the auto industry, the Reagan administration is about to put the brakes on 14 years of automotive regulation by rewriting dozens of current and proposed safety and pollution control rules.

From the car's bumper, required to withstand a 5 mph collision, to its tailpipe, whose exhaust emissions must not exceed federal limits, the automobile is undoubtedly the most closely regulated product for sale in America.

To consumer advocates, the safety improvements, emission controls and mileage requirements represent hardwon victories for motorists. The government's National Highway Traffic Safety Administration, the industry's chief regulatory adversary, estimates that safety and emission regulations added $500 to the price of a 1978 car, less than 10 percent of the purchase price.

But the industry and the Reagan administration officials argue that the rules it plans to change represent regulatory overkill whose benefits do not justify the costs to the companies and consumers.

The administration's list is expected to be announced this week as part of a program to aid the auto industry. According to industry and government sources, the list is likely to track closely the detailed requests from General Motors Corp., the industry's chief spokesman on the issue.

GM has been asking for three packages of regulatory concessions, beginning with a list of seven top-priority changes that, if adopted, would reduce GM's cost by $2 billion and save its customers $4 billion annually by 1984, according to GM vice president David S. Potter.

The priority changes sought by GM would:

Abolish NHTSA's proposed proposed passive restraint, which would require installation of airbags or automatically closing seat belts in full-sized cars beginning in the 1982 model year. The rule would be extended to intermediate and compact cars in the 1983 model year and to all other cars the following year. GM said its customers would save $70 to $100 per car if it is not required to introduce new, automatic belts; airbags would be many times more expensive, it says. The administration has already indicated it opposes this regulation.

Abolish emission rules for diesel engines on cars and light-duty trucks, which, according to GM, would require new pollution control equipment costing at least $600 per car, provided technological problems can be overcome. cThe issue needs more study, says GM. The fine particles in diesel exhaust are potentially one of the most dangerous auto pollutants.

Scrap the standards requiring bumpers to withstand a 5 mph crash and return to the previous 2 1/2 mph crash standard. The savings to consumers would be $50 per car, GM said.

Ease the pollution controls for heavy-duty trucks beginning with 1984 models to avoid installation of catalytic converters similar to those now used on cars.

Eliminate new emission regulations for 1984 model light-duty trucks, which tighten compliance requirements intended to see that the pollution controls work after extended use.

Relax the national air quality standard for ozone, a chief component of smog, and change compliance rules that would require most densely populated states to impose strict inspection and maintenance programs on cars, beginning in 1982.

The Environmental Protection Agency says that if the ozone limit is exceeded more than one day a year, states must institute inspection and maintenance programs. GM says that could cost consumers $1 billion a year. The auto maker wants that changed to permit states to exceed the limit five times in a year before they are considered in violation of the regulation.

Delay imposition of new EPA rules requiring industries to pretreat certain kinds of chemical wastes that cannot be handled by municipal sewage treatment plants -- a major regulatory problem for automobile plants.

GM's list of 36 other regulatory changes includes several that would relax programs to inspect pollution control systems and several others that require manufacturers to give consumers additional information on crash testing of cars and performance of tires.

GM also wants the EPA to put off regulation of freon, the coolant in auto air-conditioning systems, which has been banned in aerosol spray cans because of concern about its impact on the atmosphere. There is not a ready substitute for autos, GM contends.

Proposed safety rules that would require an improved rear-view mirror and installation of a high-mounted rear stop light should not go forward GM said, and it also opposes NHTSA's proposed rule requiring cars to be equipped with "anchors" for tying down the top straps of child restraint systems.

The administration's deregulation plan is sure to refire the debate about the costs and benefits of regulation and involve months of administrative hearings.

Set against the cost of automatic seat belts or airbags, for instance, are the costs of injuries to passengers who might have been protected by these devices.

If passive restraints are not provided in 1982 full-sized cars, there will likely be 600 more auto fatalities and 4,300 more injuries involving those cars, according to William Nordhaus, a member of the Council of Economic Advisers in the Carter administration. Nordhaus' recent study was sponsored by five auto insurance companies.

If those deaths and injuries could be prevented through use of automatic seat belts, the savings in lower insurance premiums for owners of the 1982 cars would exceed $200 during the life of the cars -- two to three times the cost of the restraints, Nordhaus figured.

"Nor is this calculation pure speculation," said Nordhaus.Many insurance companies currently offer a 30 percent annual insurance discount for owners of cars equipped with passive restraints, he said. (The auto industry predicts many motorists would wreck the automatic belts rather than use them, significantly limiting their usefulness).

The industry's protests about the cost of safety regulation are "phony," contended Joan Claybrook, head of NHTSA in the Carter administration. "There are only three safety requirements in the past decade that have cost more than $10 per car," led by the bumper standard, she said. "The costs are minimal compared to the harm."