I understand the rev limiter, which is what I expected. As for the radiator, we did not replace the cap, but will the second time around. Not 100% sure if there are any obstructions, and I don't know if we bled the system correctly. I can tell you that the hoses pressurized, and I noticed that the bottom part of the upper hose was hotter than the rest...did open the bleeder on the thermostat housing when we were filling it with 50/50 mix from Prestone....