If it's only been 2 years/30k miles, and there are no leaks in the system, and distilled water was used, then at this point you would probably be fine to start a regular drain/refill process without doing a complete flush. But if you wait much longer, and/or something has already caused some sludge build up (such as air in the system), then you'll need to do another complete flush to get it cleaned up again.

 

I have a regal gs and using dexcool, i didnt read all the replies so i dont know if anyone has mentioned this, dexcool will gell up if it is mixed with other coolants. As long as u dont mix it, it is fine. Havent had any problems so far

 

I wonder how many people have looked at their brown/gunked coolant in the Camaro/Firebird and assumed it's the DEXCOOL when in fact it is the power steering cooler.

 

Ive read that Zerex-G05 is great stuff... im flushing my systen this week before i put it away and using the Zerex....

also, a friend of mine has 2 LS1 FD rx-7s (one is at sema right now) and he runs green stuff

 

I worked with GM until going on my own a few months ago, and I can tell you first hand I have seen what "green coolant" does to aluminum heads if you get a head gasket leak. Not everyone is as fanatical about cars/maintenance as most here. An unchecked head gasket leak is disastrous. I had an engine myself that I got to see what it did. I bought a used car that had the green conversion done and did not know the head gasket was gone bad. On the areas of the head around coolant ports was so pocked it was almost beyond repair. We took 20tho off the heads and got a lot of it but not all. The mechanic looked at me and said, "this is why GM uses Dex, don't believe everything the internet tells you" then went on to get very technical with me as to the composition of both the green and the dex and why dex is the right choice. Its been proven time and time again, that the problem that people had with dex was in fact the sub-par gasket material that was used and failure was not the fault of the coolant. A very common one was the 3400 that they used in the Grand Am and Alero for example. If you replaced the gm gaskets with the Fel-Pro Upgraded kit in those you were good and would not see the issue again if you follow the factory recommended change interval. GM has since upgraded their kit for those cars I understand as well, but just an example is all...