Chrysler - Concorde :: Overheated And Won't Start - Replace The Engine

On a long trip (about halfway through a 1500 mile journey), I ran over a tire at 65 miles an hour. I stupidly kept going (as I was heading to the hospital to literally be with my father as he was dying). After 350 more miles (with 5 hours of rest in between) the car was showing hot (with no smells or symptoms) so I pulled into a shop. When the mechanic went out to pull the car in, it would not start. They let it cool and pulled it in, did a test and showed me a tube with the radiator fluid in it that was greyish. They told me my head gasket was blown and that the cost of repairing it was the same as the value of my car. I had to abandon the car, and rent a car to get to my dad. He died, and now I'm having to deal with the car.

The insurance company said they would cover the bumper damage but not the engine, as they could not prove running over the tire caused the engine to overheat. The car has 200,000 miles on it and is 13 years old, but had a new timing chain, pump, etc. ($1,900) of work a few months ago...and was running like a charm. There have never been any concerns about the engine in the past and the car has never overheated for any reason. I take care of it meticulously. It seems suspicious to me that there would be no link between running over a tire earlier that day, and the overheating.

When the owner of the shop put it on the lift, he says there was nothing obvious like a hose hanging down, etc., and so he thinks its unrelated to running over the tire. Because he said this, the insurance company will not cover the engine repair or give me a check for the totaled car.

I'm thinking of having the car towed to a different shop to get a second opinion. What should they look for? How can I prove this is linked? Now, the car has sat for 10 days. Is all evidence going to be gone at this point. What should I do? I have $3,000 to lose here, by giving up.