Ever since I did the body swap on my Suburban to crew cab I've had an issue with the temp guage going up to 250 on initial warm up. I have a 180* high flow thermostat (2nd one) and Windstar electric fans with a 195* thermostat on them. When I start the truck cold it warms up normally to about 200* and then the needle jumps erratically until the temp reaches 250*, then it drops back down to normal temps and doesn't do it again. I've tried two guages (mechanical), two thermostats, and checking for trapped air. I've checked it with my infra red thermometer and it doesn't show to be getting that hot at the intake where the temp probe is, but two different guages says it is. The fans are cycling on and off properly and it never purges any coolant. 
The only thing that changed in the equation from the 'burb body to the cc body was a new heater core. I didn't even drain the coolant, just pinched off the heater hoses for the swap. This never happened before the swap. Any ideas?
The only thing that changed in the equation from the 'burb body to the cc body was a new heater core. I didn't even drain the coolant, just pinched off the heater hoses for the swap. This never happened before the swap. Any ideas?
