(Adds background, details on cash burn, shares)
SAN FRANCISCO, Nov 1 (Reuters) - Tesla Inc on Wednesday pushed back its target for volume production on its new Model 3 sedan by about three months, saying it was difficult to predict how long it would take to fix all production bottlenecks.
The company also reported its biggest quarterly loss ever, sending shares down nearly 5 percent after hours as the loss was bigger than analysts had expected.
Tesla, led by Silicon Valley entrepreneur Elon Musk, faces a crucial test in its growth strategy as it ramps up production of the Model 3, its new sedan that starts at $35,000, about half the price of its flagship Model S.
Although Tesla has made inroads among luxury car buyers with the advanced technology and innovative design in its Model S sedan and Model X SUV, it is the Model 3 on which its long-term viability rests.
The company said it now expects to build 5,000 Model 3s per week by late in the first quarter of 2018 from its original target date of December.
Tesla said the main constraint was its battery module assembly line at its Nevada Gigafactory, where the company had to redesign part of the production process.
The Palo Alto, California-based company made just 260 Model 3 sedans in the third quarter due to what it called "production bottlenecks." It had planned to build more than 1,500.
Model 3 production delays mean postponed sales could exacerbate the company's cash burn, which Tesla estimated at $1 billion in the upcoming quarter. The problems could also worry the over 500,000 customers who have put down a refundable deposit on the car.
Shares of Tesla have fallen nearly 17 percent from a 12-month high of $385 in September, but are still up 50 percent from January fueled by belief in the long-term prospects of the company.
Tesla's soaring stock has made the company the second-most valuable U.S. automaker behind General Motors Co, which had annual net profit of $9.4 billion in 2016.
Tesla could face major new requirements for cash given Model 3 problems, a possible factory in China, and plans to develop other vehicles, including an electric heavy duty truck.
Tesla saw capital expenditures of about $1 billion in the fourth quarter and said it was "well capitalized" for the delayed Model 3 production schedule.
Tesla reported that cash and cash equivalents rose to $3.53 billion on Sept. 30 from $3.04 billion at the end of the second quarter, but Tesla in August raised $1.8 billion by selling debt. It also spent $325 million to repay a credit facility in the quarter.
Tesla's continued need for cash is exacerbated by Musk's insistence on vertical integration, such as making its own batteries and selling cars directly to customers. That, industry experts say, is among the reasons Tesla is nowhere close to its aggressive goal of building 500,000 vehicles annually by next year, most of them Model 3s.
Tesla posted a net loss of $619.4 million, or $3.70 per share, for the third quarter ended Sept. 30 compared with a profit of $21.9 million, or 14 cents per share, a year earlier. (http://bit.ly/2lF0H65)
Revenue rose 30 percent to $2.98 billion. Excluding items, the company lost $2.92 per share.
Tesla warned that its adjusted gross margin would decline to about 15 percent due to a higher mix of lower-margin Model 3 deliveries in the fourth quarter, but then recover in the first quarter of 2018.
Last month, Tesla reported it delivered 26,150 vehicles in the third quarter, a 4.5 percent rise on the same period of 2016.
(Editing by Shounak Dasgupta and Lisa Shumaker)