Single Point Drain issues 5.7 Magnum

halifax212

Last Fall when winterizing I knew I had an issue with the block or manifolds not draining completely. I survived the winter but now having a look at the drainage areas . After watching a couple YouTube videos, I was able to remove the drain hoses from the block and sure enough both ports were completely blocked. I managed to clear the blockage with a wire and water came flowing out. Regarding the manifold drain ports, can they be checked as well? The swivel where the drain hose is connected has me puzzled on how it works. I removed the hose but unable to push my wire up through. What does the swivel design do?  Do I need to unscrew the drain from the manifolds inspect? Thanks!