hole in thermostat

[Ali.Mouline@Eng (Ali )]

Hi All:

I recently replaced the thermostat on my 85 5000S. I noticed that the
old one had a 1/4 inch diameter hole drilled through its face. Does anybody
know why the hole is there ? I didn't drill the new one I put in. Now the
radiator is falling apart on me. The top inlet broke and I fixed that 
temporarily and now the small bypass outlet on the top of the radiator has
broken off. The plastic area around the top inlet seems to be disintigrating.
I will be replacing the radiator in a couple of days. Do you guys think
that the hole in the thermostat was relieving some excess pressure that
can damage my new radiator ??

Thanks,

ali-