Cracking Instrument cluster plastic?

I recently purchased a 2000 Century Custom and have been happy with it for the most part. When I bought it, I noticed that a small 1 inch long crack was working its way up from the bottom of the plastic instument cruster glass near the temp gauge. The crack didn't bother me that much and I ignored it.

One hot day last week when I returned to the car after work, I noticed that the same crack was now 2" long and that another 3/4" long crack had started about 3" to the right of the first one. Somehow the heat in the car and the stresses in the dashboard are causing these cracks. Anyone else having this experience?

Any idea on how to stop the process before they total crack across the whole instrument panel? It is likely that the clear plastic cover is not replacable (or available) and that I can either live with it or have to replac the whole instrument cluster.

You should be able to get the clear cover at the dealer. They get scratched when cleaning over the years and often need to be replaced.