A pair of Chicago-area General Motors dealerships is hoping to lend a helping hand to a local blood center through a rather unique promotion this weekend. Bill Jacobs Cadillac and Bill Jacobs Joliet (a Chevrolet store) are providing free oil changes to shoppers who stop in Saturday and donate a pint of blood.

In addition to the oil/lube/filter change, donators will be given an $11 gift certified to Oberweis Dairy/Ice Cream.

The “Give us a pint and we’ll give you five Quarts” event runs from 8 a.m. (CT) until 2 p.m. at the dealerships, both of which are located at 2001 W. Jefferson Street in Joliet, Ill.

The donations will be given to the Heartland Blood Center.