Larry, The lack of heat on descents is normal. As you throttle back you burn less fuel so the exhaust cools radically. Even though the rpm's may stay medium high, some of that is due to the low load as you coast down the hill.
The heat muff around the exhaust stack only gets its heat from the exhaust from the burning fuel. When you burn less fuel, the heat really drops. This is a problem during winter touch and go practice - it can get pretty cold. Solution: just drop the rpm about 200 and do a long, slow cruise descent. That might keep enough heat coming to keep you from freezing. The heat issue has nothing to do with a fuel leakage issue, except . . . When you descend, you might have the fuel flow greatly reduced yet have the engine still turning high rpms. Thus, the fuel pump may be pumping full speed while the engine is only sipping. It could, maybe, overfill the tank. This shouldn't happen if the overflow outlet is clear. You mention traces of blue on the back, bottom edge of the tank. By back do you mean toward the rear of the airplane or the "back" of the tank as you sit looking at it from the pilot's seat? Somehow fuel is getting out. This is not to be tolerated. I, as an ignorant non-mechanic might try some cotton stuffing around the tank to determine where the leak is. Let's see what those more knowledgeable than myself suggest for that. Keep the forum posted, please. Ed
