Carcraft is closing its 12-acre site at Wednesbury in the Midlands because its landlord wants to redevelop it with 200 houses.
The used car supermarket chain hopes to move to an alternative site in Sandwell, still in the Black Country.
It wants the new dealership to be more visible from the M6.
Documents submitted by GVA Grimley with the redevelopment plans reveal the growing popularity of the internet has hit trade as fewer customers are travelling to car warehouses to browse, instead researching their car choice online.
Businesses like Carcraft were switching to many, smaller sites instead, the proposals say.
Carcraft recently ranked the second most searched-for website in the automotive and dealerships category of the Experian Hitwise Top 10 Awards.
The car supermarket is about to launch an iPhone app, and launched a smartphone site six months ago.