The temperature needle used to go midway between C and H after a few minutes of driving. Now it barely gets above C, and the heater output is marginal. Everything else is fine, even on long drives. It's not cold enough here to cause this issue. I don't know anything about thermostats or the way the engine exchanges heat with the heater, but the coolant levels are normal.

1) Is this dangerous for my engine? I've driven more than 1,000 miles in this condition and everything seems normal.

2) Is this an easy fix?

Thanks.

 

Your thermostat is most likely stuck open. Its not really great for the engine, but not going to kill it either in the short term. Its a pretty simple fix. Shouldnt take more than 45 minutes to replace one.