LeArN2LiVe

Never had this problem happen before until about an hour ago. Got into my car and noticed the idle at 3000RPM for about 5 minutes then it would constantly jump from 1000RPM to 3000RPM. The car would, in about another 5 minutes, overheat past the gauge. After I parked, I also noticed all my coolant on the ground.

The strange thing though, while it would overheat I tried to turn the heater on but it would blow ice cold even though my car doesn't have A/C and the heat was all the way up.

Any suggestions?

SleepRdc2

Do you have antifreeze? Replace your thermostat if your lower hose doesn't get warm.

LeArN2LiVe

Antifreeze is spilt all over the ground. Can the tstat go bad randomly though? It was perfect last night.

deftonerider

check your coolant you might have air in the system, bleed the system

VegasInvasion

Your thermostat can go bad at any time. But the heater would be hot even if your thermostat was bad, which indicates you have no coolant, and... well that's your problem. Find the leak, fix it, and fill it back up with coolant.
Just make sure to bleed out the bubbles in the coolant through the bleeder valve after you fix it.

AWD Terror

Correct. If your temp gauge is high, your heater should blow hot. There is only two reason why it would not that I can think of:
1) There is air in the heater core.
2) The heater core is clogged.