[BirdDog]

As long as you weren't having over-heating problems, you could just keep using the green stuff (but if you do that use fresh stuff - you don't know how long it's been in there!)

If you plan to change over to the pink Porsche stuff you really need to make sure you flush out the green stuff. Make sure you turn the heat on to flush out the old coolant in the heater core. Mixing the green stuff with the pink stuff will produce a thick gel-like consistency wherever they come in contact that could impede coolant flow. Cracked heads are no joke!

Remember to cut the pink Porsche stuff 50% with distilled water. So 1 gallon of pink stuff = 2 gallons of ready to pour in coolant. The Porsche stuff seems like it's really expensive when compared to the aftermarket stuff, but Prestone is now sold precut 50/50. Cost wise they're not that different when you compare both cut 50/50.

If you are a PCA member, remember to ask your dealer for your 10% discount (most dealers do that).