[wawazat??]

Do yourself a favor and buy a small tape recorder for the meeting. Before ANY discussion starts, begin recording. Don't stop recording until you both have agreed on a resolution to your problem. When the meeting starts make sure you state the names and titles of everyone in attendance. You should have a Firestone regional manager or the franschise owner at the meeting. The shop manager probably does not have the capability to authorize an engine rebuild.

Good luck