My cap looks fine, and when I unscrew I feel pressure. Seems fine? However, I keep seeing blue coolant residue on the visible threads. Wipe it off clean, and few days later, its back. If the cap was cracked there wouldn't be any pressure build up? Not loosing coolant and temps are good. Are these plastic caps consumables? Perhaps there is something pressure related inside the cap. The hose looks good and I don't believe its leaking at that point.