Gunk in Radiator

98 Century V6 have gunk in top of radiator cap and in overflow tank..inside of radiator it appears to be clean,,does not seem to use oil,,just a standard 1/2 qt in 3000 mls..have had this car now close to 2 yrs now. I have not flushed system or put in all new antifreese,,nor do I know if this has been done in the past..Car had 65000 on when I got it and now 130000..replaced waterpump due to seal out when I got it and now seal leaking again..some where I had heard that this new pink antifreese does this with the gunk oily crap.. Or is this false?? Thanks any and all info would be welcomed on this problem..

You are correct the problem is antifreeze related. The dexcool in your car causes these issues and may require you to clean the gunk out regularly. Dexcool can also cause gasket and corrosion problems in an engine. If necessary flush the system a couple of times and use the new Prestone extended life antifreeze. Works well and does not cause the issues that Dex does.