On a new plane as they said in the other post some air my be working itself out of the system. If this does continue then check these two areas. One you are well aware of and that's just tightening any screw clamps and checking the spring clamps. If a spring clamp is too far back towards the end of the hose verses up near the bead on the metal tube the hose can weep.
The other place that gets over looked all the time is the 90 degree coolant elbows on top of each cylinder. They may not be loose to the touch, but if the seal on the threads are broken they will weep. The reason you can't usually find a lot of coolant at either location is the fast moving air flow through the cowl that sweeps the fluid away and makes your weeping area look clean. Look around the base of the 90 degree coolant elbows for tattle tale signs of coolant. Look close around the edge where it screws in and you may see a very slight discoloration of coolant. You can double check the hoses by squeezing from behind the spring clamp and milking the hose towards the open end and look for that tattle tale drop of coolant.
The elbows if oozing can be removed from the plane.Remove the elbow flange. The elbow needs to be heated well to unscrew the elbow from the flange it screws into. Clean the threads on the elbow and flange well with Lacquer thinner. You can use either Loctite 243 blue or 648 green. I prefer the 648 because it never leaks again and won't come loose from being bumped. When you apply the Loctite put it on both sets of threads and re-assemble and put it back on the engine to check alignment. I usually mark it with a magic marker before I pull it off to retain the alignment I want. Do not disturb it for 24 hours or at least over night before adding the coolant back.
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