I got a 2006 Tahoe that needed an engine. found a remanufactured (z code engine) had installed with new water pump, radiator and thermostat ( have replaced 3 times with factory 187 degree stat). Now the engine runs about 165 to 175 on the road. When idling it will get up to about 210 and will stay there all day idling fans turning on and off working normally. But when I drive temp drops back down to 165-175. Has anybody sean this and know what the issue might be? I’m checking coolant temperature with ODBII scanner and gage.