Coolant for tx series tractor ?

[wheelbuilder]

So I'd like to flush the coolant on my Bolens 1502/Iseki 2140 this spring. What's the right coolant ? The manual just says 'coolant' . Does that mean plain old 1988 green coolant, diesel with sca coolant or something else ? I was leaning towards Peak Fleet Charge, but is that right ? The tractor has an old school copper radiator from what I can tell, and has Mitsubishi's K3A, which I'm pretty sure doesn't have cylinder liners.