Aikway

I cannot figure out what is making my car run hot. It takes about 15 minutes, but gets up to 245 degrees and holds there. It starts cooling down fast as soon as I turn it off. I have replaced the thermostat, replaced the fan clutch, flushed the radiator, etc.
No noise or leaks from the water pump. The radiator looks like new, not rust in coolant or sludge. I have blown out the fins with water. If I turn the defrost and heater on full, the temp comes down about 5 or 10 degrees. I need help deciding what to try next? I took it to a radiator shop and they wanted $1,300 to put a water pump on. I declined. I see no evidence of water pump failure, other than running hot. Help please, I need my car and I am afraid to drive it. I put a heat gun on the thermostat housing and it gets up to 245. Thanks!!! Any ideas appreciated!!
Big Foot

Lee Wireless

Could have a broken impellor vane or bad seal causing air intake which will cause localized high temp issue. I'd at least take the water pump out and check it for issues. You also stated you put a "heat gun" on the thermostat. I assume your mean an IR Thermostat and not heat gun.

Aikway

Yes IR temp gun.
Thanks for the suggestion. I think I will go ahead and replace the water pump. After that, all I know to do is replace the radiator, although it looks like new and my coolant looks super clean, so I don't think there is a blockage.Thanks!!
Big Foot!