2002 Bonneville: Slight over-temp and low heater output
 

I recently had my thermostat replaced. (It was stuck half-open)
Afterwards, the temp gauge read a steady 199 after warm-up. (It has always read exactly 195 with a working thermostat, except on hot days when stopped in traffic)
The other symptom which apparently began with the new thermostat is that the heater doesn't put out air as hot as it used to. The heater hoses feel hot although I don't know if they are as hot as they should be.
I had the mechanic re-bleed the system but it made no difference. Ideas anyone?

Have you inspected the water pump? My guess is water pump or lower intake manifold gasket starting to fail. You may want to do a pressure test.

Thanks Michael.
I assume you're thinking there's a slow coolant leak at one of those locations. Would that account for the higher-than-normal temp gauge reading and the reduced heater output? Or perhaps you're thinking it's sucking air some where?

Or, you don't have enough coolant in there.