My 02 Impala has been having a hard time getting passed 150 degrees engine temp. My service vehicle light is on and I am getting a Low Coolant warning. My car doesn't leak at all when I leave it in the garage at night and i'm not smelling coolant when I drive. I just flushed my coolant out a little over a year and a half ago. How could it be low? The weather here is avg 25-30 since it's winter, but that shouldn't be keeping my engine from not reaching normal operating temp. Does anyone know what could be wrong with my car?

 

Check the codes on the car. That will help

 

I've got p0135 but I thought it was for the front oxygen sensor..