2000 Chevy Impala Low Engine Operating Temperature

A couple of years ago the engine in my 2000 impala developed a leak in the intake manifold gasket and was replaced by my local Chevrolet dealer. Prior to replacement of the gasket the operating temperature of my engine was always right around 195. Every since the gasket was replaced the engine never gets above 170. On very cold winter days it struggles to make it above 155. Is this anything to worry about? I know there is a problem with this particular engine developing intake manifold gaskets leaks, is it possible that the lower engine temperature is a result of something Chevrolet did in the repair process to lower coolant system pressure so the gasket problem doesn't happen again? Any opinions would be appreciated. Thanks.