Nasty sludge on radiator cap, filler neck and covering radia

I went to add coolant to my car yesterday and upon opening the radiator cap noticed an unpleasant sight. Everything I can see through filler neck seems to be covered in this whitish brownish goo . I hate to say it but I have not actually ever flushed coolant or anything since I got the car.. approx. 95k miles ago. I have heard it could be head gasket, but I had full engine replacement at 70k.. car now has 122k so I'd be surprised if it was that. Never had an overheating problem, I have checked the oil dipstick, looks normal. Checked the transmission dipstick, also looks normal. Power steering fluid looks good too. Could this be something that would happen because I did not have radiator filled all the way like it should be? Any help would be appreciated. I'm asking here because my mechanic is closed today and will not be open again until Monday. Don't trust anyone else around here.. I took some pictures but cannot seem to post them here. Thanks guys.. See if I can get these pictures up here.. Sorry about focus, no other camera than the one on my phone.



u didnt give the year, make model and engine size of the car but im guessing from your name that its a 2003 buick century?

if so, the spec coolant for gm is 'dexcool.' the problem with that stuff is that if it aint flushed out evry 2 yrs or 50k miles, it starts turning into sludge, and thats what it looks like u got. the fix is to do a thorough flush of the cooling system -- engine, radiator and heater core, to get all the gunk out. and dont forget to clean out the coolant recovery tank. it would allso be a real good idea while your at it to replace the thermostat and radiator cap. I'm sorry I did forget to add that in. You are correct though, 2003 Buick Century. This makes me feel a whole lot better. I will definitely keep up on all maintenance after I get this problem sorted. I feel like an idiot for neglecting the system like I did but have now realized how much I love this car and would hate for anything to happen to it. I appreciate your response Connie. I did hear about the dexcool sludging but could not find reference as to what the color might be. Again Thank you very much!! yep, dexcool aint one of govt motors bright spots. but regular maintenance will help any car last longer and run better. good luck. Car Repair Talk's forum.