I have heard that DexCool is "corrosive to plastics" which, as far as I know the only plastic in the system is the side tanks of the radiator, the connector elbows on the heater lines and heater core connections BUT- they all looked good so I figured I would just put in new DexCool and leave it alone.
I did remove the thermostat, completely flush out the system with a garden hose, poured in prestone "cleaner", ran it for a hour, drove 30 minutes of that, drained all that out, let it sit for a hour empty to cool down, then ran the garden hose through the radiator (disconnected from engine) then did the same with the engine with the t-stat out and made sure all the fluid that came out was collected. The buckets that had the most orange to them, I took to O'Reilly's. The buckets that looked like mostly water got the job of watering the backyard. (I have no pets)
As for the water, I've heard de-mineralized but our tap water here is very soft, so I figured it wouldn't be a problem. Plus, I practice agressive preventative maintenance so I won't wait 5 years/150K to do it again. The water pump on the truck is original, and I thought about replacing it, but hey- if its not broke, don't fix it. I just try to make sure I don't get a phone call from the wife bitching about being stranded somewhere in the car or truck.
Last edited by quicksilver
on Sun Dec 11, 2011 9:43 pm, edited 1 time in total.