Coolant Problem 2000gt

My 2000 gt is leaking coolant somewhere. I read about a week on this forum about the LIM gasket. There is a black sludge under the throttle body coming from the LIM gasket. Its leaking very slow about a 1/2 a gallon in about 3 weeks. My car has about 86,000 miles on it and I read about a week ago in here that after about 66,000 miles if the LIM gasket hasn't went bad than it prolly won't. Should I replace the gasket.?I know in my honda accord if I have a coolant leak it leaves a whitish green sludge behind. I don't know about the black sludge.

thanks for any advice

Its got dex-cool in it so its going to look like tar not whitish green.

I already knew that. dexicool is orange in cooler not black

From what I've read here and heard from friends who have 99-up grand am's it sounds like its the intake gasket, and my mechanic said change it before you start pulling coolant into the combustion chambers. I don't know if thats possible or not, but its something I wouldn't take the chance on. As for the black sludge, it might be coolant mixing with dirt or oil or grease or even dust, depending on what the soil is composed of where you are. Here its very sandy, so its light, but at my buddy's farm everything gets black.

Yes the black sludge is comprised of the coolant, melted gasket, and dirt. You have an external LIM leak, which doesn't directly threaten the engine, but it could rupture the inner components of the gasket and you could end up with an internal LIM leak, which would really suck, because then you would have coolant mixing with your oil, which over time will eat away at your engine bearings = destroyed motor. Your best bet is to have it changed.

The gasket can leak either (or both) coolant and oil when it starts coming apart. I think the coolant may tend to vaporize, but the oil will stick around and any dirt/dust will tne to stick to it leaving blackish deposit.

thanks guys