My resiovior keeps loosing fluid over 3 to 5 day period my rad stays full tho and always have plenty of coolant in the system resovior keeps going empty after about a week running and sitting it seems like, faster while running it seems

 

So it sounds like you have a coolant leak that only happens when the car is warm and the system is pressurized. I would start by inspecting the heater core hoses that come off the firewall and go to the engine. The drivers side one is notorious to start to tear and leak. Next, check the one that goes down the long pipe to the radiator. I dont tend to see that one fail but its possible. After that, you may want to rent a pressure test kit and pump the system up to 15 PSI and inspect for any drips. It could be a sign of coolant seal failure that is so small it is burning it off without smoke. In this case if you were to pressure test it for 5-10 minutes and then start it I would imagine it would smoke pretty bad so you would know its an internal failure then.

Some of this was word vomit, but I hope it helps.

 

If you can't find an external leak, check for an internal leak. With the engine dead cold, remove the coolant filler cap. Start the car. Do you see a steady stream of bubbles from inside the engine? Rev the engine using the throttle body. Do the bubbles increase significantly? If so, then you are probably looking at a failed coolant o-ring or a cracked iron (S4 issue mostly).

 

great.....not what i wanted to read...but i see what your saying.ill be sure to keep an eye on this myself.

 

To follow what Aaron said, I would take the advice above and either rent or purchase a coolant pressure tester. Pressurize the system to cap pressure and monitor the pressure gauge. If the pressure drops and no external leak is found then the leak is internal. Likely a faulty coolant seal, corroded channel for the coolant seal on the rotor housing or a crak in one of the irons. I would start with the pressure test and bubble test. No abnormal amounts of smoke coming from the exhaust? No leaks on the ground?