I went down a long line of used Fleet vehicles mostly Impalas and a coupe of GP with varying mileage and looked at their cooling systems (overflow bottles and radiator caps). All of them had sealing tab "sludge", but none had that redish rusty looking stuff the guy with the 96 blazer (originator of the Dex Internet postings IIRC) posted about seeing.
I'll look at my sons 99 GTP this afternoon to see what his radiator cap looks like. I know his car has had nothing but Dex, since we bought the car from the original owner and I saw his maintenance records.
