when should i replace the coolant in my 2006 malibu max what mileage?

SHPULD BE DONE AROUND 100K MILES OR SOONER DEPENDING ON DRIVING HABITS

You live in ohio great so do I. With our crazy weather patterns, if you want to change the coolant just go ahead and do it. Just open the petcock valve on radiator and drain what you can and put new coolant in. Not expensive and can't hurt anyway. Do once now and again during the summer and you should be fine for a long time.

I just looked under normal service condition 150,000 mile coolant flush intervals which is way too long in my view. I would do it at 60k