Coolant in reservoir dropping

[Bushwick]

Thanks for the info and suggestions everyone. It amazingly DOES have a bleeder screw. Can't believe it went unnoticed this entire time.

 

 

 

Still absolutely no signs of any leakage and the reservoir isn't budging. Thinking a new radiator cap is needed to be safe. I've noticed the upper radiator hose when engine is running and at temp, has basically NO give to it, which might suggest a higher than optimal pressure in the system. I seem to remember when the system was flushed after getting it 2 years ago, the hose had give. And every other car I've owned has had give too when you squeeze them. Would make some sense if the cap is seized shut as that wouldn't pull any coolant out of the overfill, though I'm surprised the pressure wouldn't pop something. Then again, this might explain the few drips noticed on the end tank before (which has since dried). Temps have been 20-30 degrees cooler, so that might be playing into things as well as the underhood heat would be higher when it was still in the 80's. Definite head scratcher.