When I first start driving for the day and my truck heats up it gets to operating temps then goes about 15 degrees above the thermostat temp then drops right down to normal running at ~177. This seemed to start after I changed to the larger radiator.
It isn't really a problem I'm just curious as to why/how it would do that. It never did this before the new radiator, that I had noticed at least. It cools off in about 3 seconds, just gets hot then drops right down to normal temps.