All taxes levied upon motor vehicles under the provisions of this act which remain due and unpaid after the date prescribed for the payment thereof shall be subject to interest at the rate prescribed by K.S.A. 79-2004a, and amendments thereto, of the tax remaining due and unpaid from the date the same became due to the date of payment and such interest shall be credited to the county general fund and retained by the county.
K.S.A. 79-5114