engine temp indicator shows overtemp,no other signs.

My engine temp indicator shows overheat to the red line, however when I stop the car I can put my hand on the radiator cap and leave it there. No signs of any leaks anywhere. The top radiator hose on the drivers side is hot. Engine runs fine. Oil on dipstick clean. I can`t find anything to back up my temp indication. Can anyone suggest what else I can look for? `87 chev caprice classic brougm ls 5.o liter. Thanks much.

My engine temp indicator shows overheat to the red line, however when I stop the car I can put my hand on the radiator cap and leave it there. No signs of any leaks anywhere. The top radiator hose on the drivers side is hot. Engine runs fine. Oil on dipstick clean. I can`t find anything to back up my temp indication. Can anyone suggest what else I can look for? `87 chev caprice classic brougm ls 5.o liter. Thanks much.

when first starting is it reading high ? if so the sender wire may be shorted to ground . low resistance will give a high temp reading.

when cold remove radiator cap. see if the coolant is flowing , rev engine see if you get good flow. see if the radiator tubes are clear and free from scale. no flow thermostat or the pump ...check belts.

see if you have bubbles in the coolant . this would indicate a head gasket. water pump pumps water not air ..any exhaust gases in the coolant the pump is useless..

corroded radiator exterior grill will also cause this high reading.

did this suddenly occur ? if so my guess the thermostat or sensor issues.