Overheating

[Trekz]

After like 15-45 min of driving the temp arrow starts getting close to red, when the heat is on. BUT when the heat is off the temp drops back to normal but windshield fogs up like crazy, and when heat is off everything turned down to cold i can still feel hot air coming out. what could be the cause of this. I know the fogging issue is probably the heat core, but would faulty heat core also couse the car to over heat when the heat is on.

[freniv]

do you lose coolant at all?
do you have a good mix coolant/antifreeze?

the only thing I can think of is that you turn on the heat which allows the heater valves to open up and circulate coolant through the heater core.. faulty heater core allows coolant to escape out. When you turn it to cold it'll close the heater valve allowing whatever coolant to circulate through the engine and cool off the engine.

[Trekz]

yah i also noticed coolant(something green i assume it coolant) leaking from somewhere, i saw it dripping off the tranny mount (the bar that bolts on the the body around the shifter area) the level was still fine not enough leaked out to overheat, i think i fixed overheating (just bleeded the system lol) but where could it be leaking from around that mid area, none of the coolant hoses that i can think of go back that far.

[freniv]

If it's green good chance it's coolant.. if it's slippery and smells sweet it's coolant. Water travels so it could be coming from anywhere. Gotta get a light in there and look/feel around.