Hi all I'm new to the forum with this being my first post. I have a Ford 3000 3cyl diesel. Trying to figure out if I have a engine cooling issue. With tractor idling around 1400rpms for about 10-15 minutes temp gauge goes into the red. Upper radiator hose is hot to the touch so I'm assuming thermostat is opening and lower hose is cool. I cracked open radiator cap with no signs of pressure and looked inside of radiator filler neck with no signs of water pump circulation. Checked coolant temp with digital thermometer reading 165F. No signs of weeping coolant from water pump. Belt is tight with no slipping. Radiator fins are clean with no debris build up. Wondering if temp gauge does not accurately represent temp sending unit? Is there anything else I should be looking for? Thanks