The company also will offer a $500 cash allowance to owners who want to buy or lease a new GM vehicle.
GM made the disclosures in documents posted Wednesday by the National Highway Traffic Safety Administration.
The loaners will be available until parts arrive to fix the switches. The cash offer runs through April 30.
GM says it isn't offering to buy the cars back. But the cash offer will be made to people who don't feel safe driving their cars.
GM is recalling 1.6 million older small cars because faulty ignitions can shut off engines unexpectedly. GM says 13 people have died in crashes linked to the problem.