Radiator - how often to service/flush, or should I?

[B.B._07]

Originally Posted by kcanaj

I had in my Yaris Dex-cool 50/50 it is the pink one, this is what Autozone gave me and I'm trying to change to Toyota brand. Should I flush first with distilled water or just drain and refill?

I really would not worry about it and leave the fresh Dex-cool in there. Contrary to what many people will tell you, Toyota pink Super Long Life Coolant (SLLC) and GM Dex-cool are nearly chemically identical as they are both ethylene gylcol based long life OAT coolant. The main difference being Toyota SLLC has some phosphate added and uses sebacate rather than 2-EHA has the main organic acid corrosion inhibitor. The other difference is the colour of dye added to achieve Toyota's pink colour and Dex-cool's orange colour (pure ethylene glycol is clear). The issues GM owners experienced with late 90's and early 00's models mainly with the 3.8 and 3.4 V6 engines where not the fault of the coolant or 2-EHA but rather a combination of poorly redesigned plastic manifold gasket, faulty radiator caps, and a lack of maintenance.

There are thousands of Pontiac Vibes running around with Dex-cool as the GM recommended replacement coolant with no issues in the Toyota powertain and cooling system. I run Dex-cool in the Yaris with no issues. If you're super concerned about it you can always change it, but flushing is not really required as the amount of coolant in the heater core is very small compared to what's in the radiator and engine block.