Engine running hot

[88ponyboy3]

Originally Posted by Blue68Coupe

So my 289 started running hot all of a sudden. I know it's been hot here but the temp gauge never moved near half let alone 3/4. I have a high flow 180 degree thermostat. I tested it on the stove and it opened right where it was suppose to.

So I took off the radiator cap and ran the engine. I did not see the radiator empty when it opened. Actually I noticed when I rev the engine the flow increases inside the radiator. That tells me is open but It tested fine.

The engine is newly rebuilt but the radiator is original. I am wondering if the radiator is not cooling it enough so the thermostat never gets cool enough coolant to close. I am leaning toward replacing the radiator.

Anyone have any thoughts on it?

fan clutch is bad i would say, start the car and watch the fan spin and then shut the engine off and watch the fan, it should not spin around after the engine is turned off but a few times