Temp Fluctations

[TX82FIAT]

The heater core acts as a second heat exchanger. The coolant quantity does not change. Opening the valve merely allows the coolant to circulate through the heater core.

When running hard up-hill on a hot day with the temp gauge climbing, turning on the heat will aid in keeping the coolant temperature under control.

Agreed. I was trying to say the same thing but i guess it came off as noise. Or my car is a little loud because of the 2.5" exhaust. In any event, No worries. The great thing about this forum is I learn something new about our cars daily. The fun talking with other Spider owners about things you have experienced or may experience is awesome and valued.

[toplessexpat]

The heater core acts as a second heat exchanger. The coolant quantity does not change. Opening the valve merely allows the coolant to circulate through the heater core.

When running hard up-hill on a hot day with the temp gauge climbing, turning on the heat will aid in keeping the coolant temperature under control.

Agreed. I was trying to say the same thing but i guess it came off as noise. Or my car is a little loud because of the 2.5" exhaust. In any event, No worries. The great thing about this forum is I learn something new about our cars daily. The fun talking with other Spider owners about things you have experienced or may experience is awesome and valued.

I think where I'm overthinking this a little is that while the quantity of coolant doesn't change, the volume does - and the pressure of the system drops ... or something ... making it less efficient at dissipating heat from the engine. Perhaps I'm just confused by the experience in my beastie, where once I turn on the heating - the temperature gauge definitely rises (albeit not by much). As said above, perhaps I just need to go a'fiddling to bleed it properly....

[TX82FIAT]

A couple additional thoughts.

I think it would be possible for coolant circulating from the head and then the heater core and then the waterpump to bypass the thermostat?

Another possability could be electrical if the temp gauge goes up a fixed amount when you turn the fan on. I have an as yet unexplained immediate 10 degrees warmer reading when i turn the headlights on.

And then there is the possability that the heater itself has some flow restriction infuencing the volume of coolant flowing in the system.

if it is not overheating and the fan is working i would not worry to much about it.

[toplessexpat]

if it is not overheating and the fan is working i would not worry to much about it.

I'm not ... more worried about that distributor swap now

A