It is expressly agreed that there are no warranties, expressed or implied, made by either the Dealer or the Manufacturer on the Buick motor vehicles, chassis or parts furnished hereunder, except the Manufacturer's warranty against defective materials or workmanship as follows:

 "The Manufacturer warrants each new motor vehicle, including all equipment or accessories (except tires) supplied by the Manufacturer, chassis or part manufactured by it to be free from defects in material and workmanship under normal user and service, its obligation under this warranty being limited to making good at its factory any part of parts thereof which shall, within ninety (90) days after deliver of such vehicle to the original purchaser or before such vehicle has been driven 4,000 miles, whichever event shall first occur, be returned to it with transportation charges prepaid and which its examination shall disclose to its satisfaction to have been thus defective; this warranty being expressly in lieu of all other warranties, expressed or implied, and it neither assumes nor authorizes any other person to assume for it any other liability in connection with the sale of its vehicles.

 "This warranty shall not apply to any vehicle which shall have been repaired or altered outside of an Authorized Buick Service Station in any way so as in the judgment of the Manufacturer to affect its stability and reliability, nor which has been subject to misuse, negligence or accident."

The Manufacturer has reserved the right to make changes in design or add any improvements on motor vehicles and chassis at any time without incurring any obligation to install same on motor vehicles and chassis previously purchased.