I had a situation very similar to yours on another vehicle. It took me a while to find it. What I had was a pin hole at the top seam of the radiator. Every time I looked to check the fan the engine was running. One day I looked under the hood after it cooled, for another issue, and saw a drop...
Oil filters
New to this thread. The thread is interesting though. Some mention of filters here, so I have a question for the 05 GT 4.6 owners. What size filters are you using? I bought this car 2 yrs ago with 54K miles and its very clean. Part books keep leading me to the large diameter/short...