Trying to sort out some swap cooling issues... Options

[aspen]

I've still got some cooling issues on the BEAMS.

Here's the deal, I've got a new radiator, new OEM thermostat, new hoses, new water pump and new temperature sensor. (I want this swap to run for quite a while).

Still have some cooling problems though where it'll run hot, and the temperature gauge will behave somewhat erratically. I hooked up OBD to it and the ECU reported around ~95C with the needle close to the red. Of note, I tested my 82C thermostat and it opened, but maybe a bit higher than 82C (it's not the most accurate thermostat in the world) but it still seemed maybe a bit strange?

I'm pretty confident the system is completely bled, and heat works. The top radiator hose gets hot but the bottom one less so (though, shouldn't the coolant going into the engine be pretty cold anyway?)

I ran the engine briefly with no thermostat and just water and it also got surprisingly close to operating temperature (I didn't drive it though) on a maybe 90 degree day.

Thoughts?

[lagos]

The wiring is a consideration of mine - mostly because I did it. (Extending the harness anyway). So it sounds like in general it should report a bit higher than what the thermostat is rated for? (Makes sense, it's coming right off of the engine block).

It's definitely filled, I've filled and bled the thing quite a few times with the same results. The radiator fans are triggered by the coolant radiator sensor at the bottom of the radiator, which given the fact that my radiator seems to be doing a good job of cooling, I wouldn't expect it to still be 200F at the bottom of the radiator.

I'm not talking about that sensor. I'm talking about the readings taken from your engine temp sensor.
On my megasquirt EMS, I see temps in the 185-200ish once the engine is at full operating temp. At 200F ENGINE TEMPERATURE, the cooling fans turn on. During this whole time, the temperature reading on my gauge cluster stays in the middle and does not move at all.

If yours shows similar behavior at idle with the scan tool, then the problem is just with an incorrect gauge cluster reading and not an engine cooling issue.