I have a 2016 and for the past year or so I have noticed my coolant keeps dropping slowly. The cap is hard to turn or remove and install. I have looked for leaks and have not found a leak anywhere on the truck. The only thing I have noticed was the overflow tube has white and pink residual on it and coolant seems to be coming from there. I have also noticed that the coolant seems to leak when the RPM's are higher. I went to fill the reservoir yesterday and as soon as I got to the middle or add mark it started coming out the overflow tube. It would not allow me to add coolant all the way to the full line. I have no white smoke and truck runs very well currently, I'm at a loss. I have ordered a new reservoir and will install as soon as it arrives. hoping that is the issue. Let me know what you guys think. Thanks.