FREMONT — Tesla Motors shut down its production line Monday as part of a long-scheduled plan to retool the factory to increase production of the Model S sedan and prepare for the introduction of the Model X crossover SUV.

“We’ll be back at regular production Aug. 4,” Simon Sproule, Tesla’s vice president of communications, said in an interview. “We’ll be down for 128 hours of regularly scheduled production time.”

The new production line, which will cost roughly $100 million, is on the ground floor of the factory off Interstate 880 and will be used for both the Model S and forthcoming Model X.

“It improves the overall flow for the plant,” Sproule said. “We’re installing new lines, reconfiguring the plant and making more use of the available space in Fremont.”

Sproule affirmed the guidance Tesla has given to investors, saying the Palo Alto electric car manufacturer remains on track to produce and deliver 35,000 Model S sedans this year and should reach a run rate of 1,000 cars a week by the end of the year. The company is also expanding its powertrain and battery pack assembly areas on the Fremont factory’s third floor.

Tesla purchased the Fremont plant in 2010 and began Model S production in 2012. It describes the upcoming Model X as blending “the best of an SUV with the benefits of a minivan, as only an electric car can.”

Tesla’s Fremont workforce, which includes more than 3,500 employees, will be largely unaffected by the stoppage and workers will still earn their paychecks.

“Employees can come to work as normal and do training and maintenance, or they can take paid time off,” Sproule said.

In a May earnings call, Tesla CEO Elon Musk told analysts that the factory was likely to be idled sometime this summer to enable a substantial increase in production capacity.

Tesla is also in the process of evaluating possible locations for its “Gigafactory” for battery production. The company has said it is studying sites in five southwestern states: Arizona, California, Nevada, New Mexico and Texas. California has long been considered a long-shot for the massive, 10 million-square-foot facility, which will cost as much as $5 billion and is expected to employ 6,500 people. But state officials are eager to land the Gigafactory for the Golden State.

State Sens. Darrell Steinberg, D-Sacramento, and Ted Gaines, R-Rocklin, have introduced legislation to entice Tesla to build the Gigafactory in California. The bill is on hold until the Legislature returns from summer recess.

Tesla plans to report earnings for its second quarter, which ended June 30, after the closing bell on July 31.

Contact Dana Hull at 408-920-2706. Follow her at Twitter.com/danahull.