Full coverage is a phrase meaning that you have Comprehensive and Collision coverage on top of required Liability coverage.

Comprehensive covers your vehicle for such things as hail, tree falling on it, vandalism, etc. These are less likely occurences and the reason why it's usually an inexpensive coverage.

Collision covers your vehicle if involved in an accident, you hit something, etc.

If your motor was destroyed by any of those means, then you could claim it. But unless you have a really good story and are OK w/ taking chances on submitting a fraudulent claim, I don't think it'll work out for you.

Also keep in mind, depending on the value of your vehicle, needing a new motor could constitute your vehicle being a total loss. In which case they take the car and give you a check.
Is it the FC or FD that may need it?