Hello everyone, new guy here. I have a 2005 Chrysler Sebring 2.7/Touring. The coolant it uses is orange HOAT G-05. I bought it 2 months ago with 133k and I'm not sure if the coolant has EVER been changed. I tested the coolant and it's freezing point is at -33F. Would it be fine if I change it at 150k or is it "critical" that I change it a.s.a.p? I'm little worried if my car has scale/rust in the cooling system.