Goodyear Tire & Rubber Co. reported a third-quarter loss while B.F. Goodrich Co. said its earnings for the period were almost unchanged despite a sharp decline in income from its tire operations.

Both rubber industry giants had gloomy projections for the final quarter of the year.

Goodyear, the nation's No. 1 rubber maker, reported a third quarter loss of $7.3 million (10 cents a share) on sales of $2 billion. That compared with earnings of $45.5 million (63 cents) on sales of $1.9 billion in the same period a year ago.

Goodrich had third quarter earnings of $16.8 million (99 cents) on sales of $742.9 million. That compared with earnings of $16.6 million ( $1) on sales of $648.2 million in the same 1978 period.

Goodyear Chairman Charles J. Pilliod Jr. attributed the loss to a drop in demand for cars and tires during a period when the company faced extensive expenses associated with plant closings.

For the nine months ending Sept. 30, Goodyear reported earnings of $94.5 million ($1.30) on sales of $6.2 billion. That compared with earnings of $154.5 million ($2.14) on sales of $5.5 billion in the same 1978 period.

For the first three quarters, Goodrich reported record earnings of $67.7 million ($4.02) on sales of $2.2 billion. That compared with earnings of $49.8 million ($3.18) on sales of $1.9 billion in the first nine months of 1978.

"An exceptionally strong performance by our chemicals group helped offset the adverse effects of poor tire sales and escalating raw material, energy and labor costs in practically all our businesses," said Goodrich Chairman John D. Ong.

Knight-Ridder Newspapers Inc., reported a 32.7 percent earnings gain for the third quarter yesterday.

Net income was $21.38 million (65 cents) on revenues of $243.03 million compared with $16.1 million (49 cents) a year ago on revenues of $212.8 million.

For nine months, Knight-Ridder earned $63.9 million ($1.94) on revenues of $712.76 million compared with $53.73 million ($1.64) a year ago on revenues of $636.03 million.

Gannett Co., owner of newspapers and broadcast stations nationwide, reported yesterday its earnings rose 18 percent in the third quarter and 20 percent in the first nine months of the year.

Gannett's net income for the third quarter was $32.1 million (90 cents) compared with $27.2 million (77 cents) for the same quarter last year. Operating revenues for the third quarter totaled $261.5 million compared with $238.1 million for the comparable period in 1978.

For the first nine months of this year, Garnett said, operating revenues were $769.5 million, income before extraordinary items was $92.5 million, and earnings per share were $2.59.

During the same period last year, Gannett reported operating revenue of $696.4 million, income of $77.2 million before extraordinary items, and earnings per share of $2.19.

Aluminum Company of America reported earnings yesterday of $107.4 million ($3.04) compared with $83.8 million ($2.39) for the same period a year ago.

Alcoa said profit for the first nine months was $369.5 million, ($10.47) compared with $212.5 million ($6.05) in 1978.

Revenues for the third quarter were $1.172 billion, against $1.016 billion in 1978. Sales for the nine months were $3.556 billion, against $2.969 billion.

General Telephone & Electronics Corp. earned 99 cents a share in the third quarter, down from $1.09 a year earlier.

Third quarter net was reported at $144.72 million against $155.31 million a year ago. Revenues were $2.473 billion billion against $2.154 billion a year earlier. Nine months net was $444.17 ($3.06) down from $3.11 a share a year earlier. Nine months revenues rose to $7.168 billion from $6.286 billion.

American Express Co. repored record earnings for any quarter and nine-month period in its 129-year history.

Net income for the third quarter ended Sept. 30 rose 11.8 percent to $97.9 million ($1.37) from $87.5 million ($1.23) in the comparable period of 1978, the company said. Revenue in the latest quarter rose 14.6 percent to $1.21 billion from $1.06 billion in last year's quarter.

The international banking and investment services firm, best known for its credit cards and travelers checks, reported revenue of $3.4 billion in the nine-months ended Sept. 30, a 14.6 percent increase over the $3 billion reported in the comparable period of 1978.

Net income for the latest nine-month period amounted to $262.8 million ($3.68) a 12.1 percent increase from the $234.4 million ($3.28) reported a year ago.

The Dow Chemical Co. reported third quarter sales of $2.43 billion, up 46 percent from sales of $1.67 billion in same period last year.

Dow said its net income in the third quarter was $198 million ($1.09) compared with $153 million (85 cents) in the third quarter of 1978.

Southeren Pacific Co. doubled its earning in the third quarter to $1.15 a share from 58 cents last year despite losses in its railroad operations.

Net income for the quarter was $30.8 million on revenues of $673 million, up from $15.6 million on revenues of $561.8 million in the third quarter of 1978.

Nine months earnings were $123.1 million ($4.57) on revenues of $1.9 billion, compared with $62.6 million (2.32) on revenues of $1.7 billion for the same period of 1978.

Giant 3M Co. reported earnings for the third quarter yesterday rose 13.7 percent to $1.48 a share from $1.31 in the same period last year despite "global uncertainties" and the administration's price guidelines.

The firm had earnings of $174.3 million on revenues of $1.42 billion compared with profits of $153.4 million on sales of $1.224 billion in the third quarter of 1978.

Nine months earnings were $488 million ($4.16) on sales of $4.07 billion, up from profits of $415.7 million ($3.57) on sales of $3.47 billion in the like period last year.

Seaboard Coast Line Industries Inc. reported earnings of $2.10 a share for the third quarter, up from only 27 cents a year ago.

Nine months profit was $87.3 million ($5.97) up from $36.61 million ($2.51) a year ago.

Revenues for the quarter rose to $537.55 million from $460.94 million and those for nine months to $1.592 billion from $1.384 billion.

Weyerhaeuser Co., the forest products giant, reported earnings of $1.03 a share for the third quarter, up from 70 cents a year ago.

Net income was $131.6 million on sales of $1.173 billion compared with $91.25 million a year ago on sales of $949.22 million

For the year so far, Weyerhaeuser reported profit of $402.74 million ($3.17) on sales of $3.305 billion, up from $276.02 million $2.11) last year on sales of $2.738 billion.

Allegheny Ladlum Industries Inc. earned $1.45 a share in the third quarter, up from only 42 cents a year ago, as sales climbed to $394.21 million from $309.38 million.

Net income was $15.39 million against $7.47 million.

Nine months net was $50.82 million ($5.05) on sales of $1.71 billion, up from $25.34 million ($1.59) a year ago on sales of $975 million.

Pepsi Co., the country's second largest soft-drink maker, reported 16.5 percent earnings gain in the third quarter and 19.5 percent gain for the first nine months of the year.

Pepsi Co., which also produces snack foods and operates a pizza restaurant chain, said net earnings in the three months came to $80.59 million (86 cents) up from $69.12 million 74 cents a year earlier. Sales for the quarter were $1.28 billion up from $1.09 billion a year earlier.

For the first nine months of the year, the company reported earnings of $198.3 million ($2.12) on sales $3.48 million ($1.79) on sales of $2.95) billion.

Johns-Manville Corp. announced its earnings in the third quarter rose 27 percent on a 40.6 percent jump in revenues. But nine-month earnings-per-share still are down from a year ago.

Johns-Manville, a Denver, Colo. based manufacturer of a variety of building products, said it earned $34.8 million ($1.29) on revenues of $616.9 million. That compared with earnings of $27.4 million ($1.26) on revenues of $438.9 million in the comparable 1978 quarter.

In the first nine months, Johns-Manville earned $87.5 million on revenues of $1.68 billion. That compared with profits of $87.3 million ($4.04) on revenues of $1.22 billion in the first three quarters of 1978.

Braniff Airlines reported a loss of $9.8 million for the quarter, compared to a profit of $15 million, or 75 cents a share, a year ago. The loss came despite a 35 percent increase in revenues to $370.7 million

Strong performances by its international division and domestic pharmaceutical business led a 16.1 percent increase in Bristol-Myers Co.'s third quarter earnings, the company announced yesterday.

Bristol-Myers, the diversified maker of personal and home products, said it earned $67 million ($1.02) compared with $57.7 million (88 cents) in the comparable 1978 quarter.Sales rose to $731.2 million from $644.2 million.

In the first nine months this year, Bristol-Myers had net income of $169.9 million ($2.57) compared with $147.9 million ($2.24) in the first three quarters of 1978. Sales for the period were $2.04 billion compared with $1.82 billion.

W.R. Grace & Co., the diversified manufacturing concern, had lower earnings in spite of higher sales in the third quarter.

Net income was $42.59 million (97 cents) on sales of $1.278 billion compared with $43.08 million ($1.01) a year ago on sales of $1.044 billion.

Nine months profit was $157.59 million ($3.59) on sales of $3.78 billion compared with $132.07 million ($3.11) a year ago on sales of $3.21 billion.

R. J. Reynolds Industires Inc. declared a 2-for-1 split of commons stock yesterday after reporting a 10.5 percent increase in its quarterly dividend, the largest since 1961.

Reynolds reported consolidated revenues of 2.23 billion for the 1979 third quarter, up $554.4 million over the three months of 1978. It reported revenues of $6.45 billion for the nine months ended Sept. 30, a 30 percent improvement over the same period of 1978 which did not include Del Monte's results after its February merger.

Reynolds' net income of $147.6 million in the third quarter increased $34.5 million over the same period of 1978. Per-share earnings in the quarter were $2.77, up 46 cents or 20 percent over the same period of 1978.

For the nine months, the corporation's net earnings were $415.9 million in 1979, a 30 percent improvement over the $319.9 million reported in the period last year.

Nine-month per-share earnings were $7.95, up 22 percent from $6.57 in the first three quarters of 1978.

Bunker Ramo Corp. reported third quarter earnings yesterdsay of $6.5 million ($1.02) compared to $4.6 million (73 cents) for the similar period last year. Nine months' earnings were $17.2 million ($2.69) compared to $11.8 million ($1.86) for the nine months of 1978.