Thermostat to suit 4AGE

[Cee-Lo]

I will be replacing the coolant in my AE93 Corolla with the redtop 4age motor. Going to replace the thermostat as well. Just wondering, what temp rating thermostat do I need, and is there a specific part number for it, or are all thermostats the same size, with only the temp they open up being the difference between them?

[eviltwin]

Is the current thermostat faulty? if it's not don't replace it.

[Cee-Lo]

Not sure if it is faulty. As the coolant is rust colour, I'm thinking it may be a good idea to replace the thermostat as well. Car has never overheated, gets up to slightly under 1/2 way on the temp gauge at most. But it can take a while to get up to operating temp on colder days. Car does run a bit rich also.

[CHA54]

replace the thermostat with a genuine part, while the coolant's drained take the radiator to a radiator place to have the core unblocked. They remove one of the tanks and clear the core tubes with a steel rod. If it's never been serviced before it will be at least 40% blocked.