My dearly beloved has recently been running a little hotter than usual. Usually it runs 210 lately it rises to 230 and then goes down when i turn the heater on. Here is the deal I am not actually running the heater just turning it on and then immediately turning it off since it isn't that cold yet. It is not a water pump issue or a radiator issue since those were replaced last spring. Any ideas?

 

Sounds like a thermostat or a blockage of some kind. Mine rarely gets over 200. Only when its about 100d outside and I'm sitting at a drive through.

 

thermostat could be stuck, so when you turn the heat on its cooling the engine. but without the heat there isnt enough flow through the radiator to cool it.

 

When you run the heat, the temp goes down, right?

I'd say start simple. Drain the system, flush the system (radiator, heater core and engine block separately), throw in a new thermostat and fill with 50/50 coolant.

After that, see if the problem persists.

Another major component of the cooling system you have not addressed is the mechanical fan clutch.

Also, make sure your electric fan is kickin on when it is supposed to.