Citing demand and oversupply issues, General Motors is idling the factory making four different car models, including the Chevrolet Volt plug-in hybrid.

The Detroit-Hamtramck Assembly plant will experience a reduction in vehicle output starting next Friday, Oct. 20. This will lead into a month-long wind down of production, culminating in a full shutdown on Nov. 20.

According to company spokesman Tom Wickham, the shutdown is expected to last through the end of this calendar year.

As of Oct. 1, Chevrolet has roughly 6,000 Volts in inventory, a 107 day supply. That’s an increase of 10 days from one month ago.

READ MORE: August Chevy Volt Sales Down 30 Percent

It is worth noting that the Volt’s irritatingly-phonetically similar cousin, the Bolt, has been getting the lion’s share of GM’s EV marketing dollars since its introduction. With focus on the 200-plus-mile range of the Bolt EV, the Volt hybrid has all but disappeared from automotive news coverage. Its relative obscurity can’t be helping sales.

In addition to the Volt, Detroit-Hamtramck also assembles the Buick LaCrosse, Chevy Impala, and Cadillac CT6. Of the four models, GM is dealing with a 106-day supply of the CT6 and a massive 284-day supply of the Buick sedan, according to industry publication Automotive News.

Those numbers are well above the accepted industry standard of just 60 days. To put the LaCrosse figure in perspective, GM could stop making the sedan today and, at current rate of sales, not need to build any more until after watching the fireworks on Independence Day.

“As a result of declining overall industry volumes, the Detroit-Hamtramck plant will be making schedule adjustments to keep supply and demand in balance. Effective Oct. 20, the plant will operate under a reduced production schedule,” according to a GM statement. “This action will help maintain more stable production.”

The company says it expects less than 200 of the 1,800 workers at the facility to lose their jobs as a result of this action. All employees will be idled during the shutdown.

Currently, Detroit-Hamtramck Assembly employs 1,580 hourly and 220 salaried employees. Since opening in 1985, Poletown has produced more than four million vehicles.