If the pipes don't warm up that's a sign that contact from CPU to the heatsink system may be non-existant. The CPU would heat up, but not the pipes.
Whenever I start my computer, I go to my Bios and it says my cpu is rapidly heating up, 49C to 70C in about 5 seconds. It auto shuts down since it gets to 70C, I go to feel the conductive pipes my heat sink has, and it's cold. It has only recently done this when it was overheating legitimately, and I replaced 3 fans I had in the system that broke. I can't even get to the desktop before it shuts down.