It will depend on your state and the arbitration/disagreement clause in your auto policy.

Your recourse is likely to come about by seeking legal counsel and find out if your state laws would allow you to argue the findings.

If you prefer to handle it without legal counsel, you can ask for another adjuster or have an independent adjuster evaluate your vehicle and submit their findings. Most likely, if you have to fight with the insurance company you will need to get a 3rd party adjuster to substantiate your claim that the vehicle damage was caused by something other than mechanical malfunction.

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