Yesterday I started my car and the idle started to fluctuate up and down. I let the car warm up but it was still fluctuating. After driving for 30 minutes, my heater started getting colder until it was no longer hot. I noticed my engine temperature was OVER THE ROOF! I stopped and noticed there was smoke coming from the anit-freeze coolant unit. I checked and noticed it was empty so I poured some in. After starting my car, the Heater still does not work and the engine still over heats. Please help me if you know what could be wrong.

 

You've got a leak somewhere. The idle bouncing was telling you the coolant was low. I hope that you are using a good mixture of antifreeze-based upon where you live. Anyway, you'll need to find the source of the leak, repair/replace. Then when adding coolant back, make sure to bleed the air out of the system.....and all of this is hoping the overheating didn't cause other damage.

 

Coolant issues, maybe blown hose or something?

 

I'd see if there's any leak behind the block on the timing belt side in case the water is bad. I'd inspect the heator core coming from the head and back to the heater valve. Also check the heater valve located at the firewall cause these are known to get stuck close and won't let coolant flow to the heater core to give off heat.

 

Turns out I just needed to change the thermostat and refill my coolant and idle issue is because of the low coolant. Thanks for the help!