[AKnowles]

No condensation is normal. it sounds to me like your engine compartment may be running hot. If you are losing coolant, I'd suggest you stop driving it until you determine where the leak is coming from or possibly have serious damage. I think you should either crawl under the car and check the water pump or pull the engine access cover and check it.

If you keep pulling air in the system, you need to burp it to release it. Plus air in the system can damage your water pump. If it is not already the problem. Really, I think you should get it checked out if you can't do it before you have serious problems.