About 2 months ago I had my coolant flushed and hoses replaced and I've been monitoring the fluid levels lately to make sure everything is ok. My last inspection shows my coolant level well below the minimum. There are no leaks that I can see and no puddles or anything under the car. I checked my oil to see if it could be a head gasket leak which would cause a milky color but my oil is nice and clean. Is it normal to go thru this much coolant? My temp gauges have all been normal and I don't really drive the car to hard. I'm not sure why the coolant seems to be slowly disappearing. Any ideas?

 

See any white smoke in the exhaust when you start the engine? Coolant can leak into the oil system, or also into the combustion chambers. White smoke indicates the latter.

How much total would you say has gone missing in the last few months? Perhaps it's just some residual air working its way out of the system. Try driving with the heater on for a while, too, in case there's still some air in that part of the circuit. If all else fails, take it to a shop and get a leak-down test.

 

There's no white smoke in the exhaust. Since it's been cold out the past couple weeks here I been running the heater on my way to work in the morning. You might be right about the air bubbles cause ever since I started running the heater is when I noticed the most drop. I just didn't realize it would drop so much from having air in the lines. It went from max level to way below minimum.

 

I say air bubble since you had coolant flushed, they probably didn't burp the system correctly. It has finally gotten colder and you turned over to heat and it came through.

 

Air in the system. How much is well below minimum? How much have you added since you bled it?

 

It's possible to have a very small leak on the block that evaporates before it has a chance to pool up and it only leaks when the engine is hot (metal expands). You can try a UV dye to see where the leak is. Also, you could try to do a hydrocarbon test to see if you have a leaking head gasket. The coolant and oil don't always turn milky.