Does the coolant have a foul odour? If it were Glycol we were talking about, was it bright green [just a note to other readers]. I'm not 100% sure about dex, but I think when it'* old it smells bad.. I KNOW that is true for glycol, smells just like cat ****. Like straight 5-year-old cat ****. You'll know when that coolant is gone.
Flushing does take more time, but I would never mess with my cooling system without doing that. You don't NEED a kit to do it.. but I hear it makes it easier. I can do without, but I am poor, and can take a lot of frustration.
'89 SSE - GX3 -190k, 155k on body - Back for another ride.