I was driving to work today and had the heat blasting, and then it went straight to freezing. Now the past week or so, my low coolant light flips on and off, and the past couple days its been off. I know its a "dummy" gauge, but the stock temp gauge in the car was a little below the middle mark. When I got to work, the heat kicked back on, and the temp gauge went all the way to the right like it was overheating. I parked it, the temp needle went down, and I lost heat again.

I'm assuming this has something to do with my coolant level, but any ideas?

 

It sounds like a sticking thermostat to me.

 

The low coolant sensor is inside of the overflow bottle , so when the engine is cold there is less coolant in the bottle and can trigger the light on and off.

Living in ohio I use a 75/25 mix of antifreeze . Even though the bottles of antifreeze say a 50/50 is good for -40 degrees I don't trust it Ive had ice in my radiator at -10 using 50/50. I don't know what your night time temps have been ranging where you are but here it has hit well below 0 at night with a -windchill factor. I would say you need to add some antifreeze to the system and get the air out of it.
Air in the system causes all kinds of odd stuff to happen

 

How do you get the air out of the system?

 

You need to fill it with coolant and run it with cap off till the thermostat opens . Watch the coolant level in the radiator and it will drop then fill it back up . Sometimes it helps to jack up the front of the car. And it may take a few times. But if it has air in it that means your loosing coolant someplace. You should figure out where its going.

 

There's a leak at the Tstat housing. My engine's so close to being done, I didn't see the point in messing with fixing it especially in this cold. This car seriously has to last just another couple of months lol.

 

The cap to the overflow or the radiator?

 

Ha well If it only needs to last a couple months make sure you keep some antifreeze on hand. Never use plain water to fill it when it gets low or you will have ice in the system , ,, , ( NOT GOOD ) lol. Just keep an eye on it and fill it once in a while.