thanks for your service! how can i manually check coolant temp to see if gauge is accurate or if water pump working properly? temp gauge goes almost to red line when driving. literally within a minute or two. cools down at idle and when heater on high. heater fan blows hot air, no coolant loss, no oil in water, no water in oil, no coolant out exhaust pipe, passed the chemical test for exhaust in coolant. top hose gets very hot but i really cant feel water running through it. top hose squeeze pushes coolant out of radiator fill neck. bottom hose is warm. radiator looks new and drains quickly from the petcock. i have seen the overflow reservoir raise a couple inches after driving and returns to radiator when cools down. just replaced thermostat, previous owner states water pump replaced about a year ago. temp gauge acts like a rpm gauge when at idle and rev it up. i bought this beater to go to grammy in ft lauderdale for going to doctors and grocery store because the air blows very cold and thought it only had a rear wheel bearing issue. im trying to avoid buying sending units for trial and error.
You don't want to open radiator cap while engine is HOT-- to avoid scalding yourself. Instead, employ drain petcock on BOTTOM of radiator: drain 1-cup of coolant when engine is hot-- use insulated gloves again to avoid burning yourself. Now you can safely take temperature of that fluid. Ensure to use a thermometer properly gauged for heat that high so you don't get mercury everywhere or use digital thermometer.