General Motors Corp. yesterday reported record profits of $528 million for the third quarter.

Sales for the world's largest manufacturing organization were also a record at $13.6 billion for the quarters. It was the fourth consecutive year that GM has shattered its third quarter sales and profit record.

GM's payroll totaled $4.2 billion for the three month period, and total factory unit sales of cars and trucks was just short of two million at 1,982,000. All were new records for any auto maker.

The third quarter figures put GM's worldwide vehicle sales up 10 percent, dollar sales up 19 percent, and profits up 31 percent compared to the same 90 day period in 1977.

But GM said its profits as a percent age of sales had again fallen, to 3.9 percent in the three month period. The record levels in every category, except profit as a percentage of sales, held equally true for the first nine months of 1978.

GM chairman Thomas A. Murphy and president Elliott M. Estes said in a joint statement that the increase in profits "resulted primarily from higher volume and improved operating efficiency" which were trimmed slightly by increased costs for materials and labor, plus spending for tooling and facilities related to coming new model programs.

"For comparative purposes, the corporation's profit margin is currently below the levels achieved the first nine months for the past 20 years," they said.

GM's dividends on common stock for the first nine months were $3.50, compared to $3.55 a year earlier. The automaker's earnings had been expected, and followed by one day relatively similar results from Ford Motor Co. Unlike Ford, however, GM separates its overseas results from its domestic results only on an annual basis.

GM said it had set aside $443 million in the three month period for U.S., foreign and other income taxes, and a total of $2.2 billion for the nine month period. For 1977, those tax provisions were respectively $328 million and $2.1 billion.

Murphy and Esters said they think "a strong base exists within the economy to support further economic expansion," and added "Our overall assessment of current economic conditions is optimistic.

"We believe the prospects for a continued high level of motor-vehicle demand appear excellent," they said.

LTV Corp. and Lykes Corp., two documents with the Securities & Exchange Commission pertaining to the proposed merger, reported a $759,000 loss, compared to a $24.7 million deficit in the period a year ago.

Lykes said it made $1.18 million in the third quarter - compared to a $117 million loss a year ago - but that dividend requirements for the conglomerate's preferred shares wiped out common share earnings.

Aetna Life & Casualty Co., the insurance giant, earned $2.53 a share in the third quarter, up from $2.38 a year ago.

Nine months' profit was $6.84 a share against $5.87 a year earlier and shareholders' equity rose to $44.30 a share from $36.80.

The company had a loss of $9.61 million on capital gains for the nine months, which was offset partly by a $2.46 million tax credit. Net income was $369.42 million against $315.63 million a year earlier.

McDonnell Douglas Corp. announced third quarter earnings of sharply from earnings of $29.3 million (76 cents) in the same quarter last year.