Bad thermistat, or somthing worse?

[Dixon905]

I drive a 420a, it has treated me good for the most part. But I had just noticed that my temperature gage was higher than normal, so I kept my eye on the gage ,and started to accelerate then all of a sudden, it had jumped up to almost red line. I wad instantly scared, so I had pulled over popped the hood checked my antifreeze, it was right below the medium mark, and my oil was fine. I am stummped! My car has 147000 miles on it and it needs a head gasket soon, dose that have anything to do the the gage spiking. I need help!

 

[DJ Raydiate]

The 420a does not have a belt on the water pump/alt. the water pump on our cars (420a) is driven off of the timing belt.