In addition to flushing out the incorrect coolant and using spec coolant:
1.) Get new o-rings for the water pump and thermostat housing where they slide onto the water pipes on the engine. Be sure to lube with "soapy water" before sliding the water pump on per the shop manual.
2.) Use the correct FIPG seal packing at the flange where the thermostat housing bolts onto the water pump.
3.) Use an accurate torque wrench on all bolts, tightening in steps from the center outward. I usually divide the final torque by 3 and use that as the increment, e.g. for 24 N*m bolts, first pass is 8 N*m, then 16, then 24, and a final pass at 24.