2000 Impala cooling problems!

I have been having a problem with the coolant, I keep on getting the
low coolant level light that keeps on coming on. I checked the coolant
and it is a little low maybe 2 cups of fluid . But around the neck of the
radiator is this lightbrown sludge. So I flushed it and refilled it with
new dex cool , and two weeks later that light came on again. So this
time I flushed it and added a radiator flush and drained that,and added
more dex cool . And two weeks later the light came on again so I replaced that sensor. But two weeks later the light came on again.
So I took it to a garage and they checked it out and told me that
I needed intake gaskets. But the quote was a little over priced
so I replaced them my self . But when I was working on it I noticed
that the fans were not working. So I checked the fans by jumping
them across the battery and they work. So I thought that the relays
could be bad and replaced them, but fans still did not work. Thats
when I decided to check the temp sensor and I unpluged it and they
came on. But back to the gaskets Iam not sure about the torque
spec. for the lower manifold I am finding differant specs.. And I
have been talking to other people about dex cool and finding bad things
about it. Could that have caused this problem.

yes and GM has a updated gasket out for i assume the 3.4 is what you have you should have asked at a GM dealership service dept but call them first thing im sure they will help you out or at least give you the proper gaskets what worries me did any fluid get in the the internals of your engine if it did you must know that your engine will not last much longer or it might with some damage

well the dex cool is not what caused the probelm. and yes these cars are known for intake problems and coolant leaks, the 3.4 and the 3.8. my brother in laws friend works as a machanic for chevy and he was helping me with my brake lines and he asked if I had problems with the intake leaking coolant. I said no I have the 3.8 not the 3.4. he said that doesnt matter, the 3.4 have problems with the lower intake manifold and the 3.8 have problems with the upper, or its the other way around, I dont remember.

but you may have a small leak somewhere else, maybe double cheack the radiator cap, I took it off a few times and it was a major pain to get all the way back on, I relly had to push harder than any other car ive worked on, so maybe it might not be on tight enough and leaking there. or what happened in an old car of mine, is that the coolant sensor was in the resivouir(stupid ass place if you ask me) so if the resiviour got low it said low coolant, and there was a small hole in the resiviour, not the cooling system, so you might want to check there too.

or just start your car and drive it around to get it up to temp, then go home adn keep it running and just sit there and wait for it to start to get hot or "overheat" and see if the fans turn on at all when there supposed to(they have a low and high function) and just watch it to see if you see dripping or leaking coolant when its running.

otherwise I dont really want to copy this and send it to a guy over at naioa just to be like"hey fix this problem for this other guy" but this guy is a master when it comes to electrical shit so if you go to the naioa forum and post your problem, he'll probably see it and could most likely tell you why the fans only come on when the sensor is out. this guy is amazing when it comes to anything electrical, he makes so much mods for our cars, right now im waiting for my package to come, its to shut off the DRL/ALC with the flip of a switch with no splicing, just plug and play. hes awesome and he might be able to tell you why that sensor thing is happening. you just have to make sure that whenever or wherever you get an answer for that, post the fix here because im sure more people either have, or will encounter the same problem.

sorry I cant be of more help.

First of all, i hate Dex-Cool, which is why i run green antifreeze and change it every 30,000 by GM specs. Second of all, if you still have a leak after the gasket change, you may want to check the thermostat housing bolts and make sure there's no seepage there. The last 3.8 gasket change i did was a head scratcher. After replacing all gaskets, i still had a leak. After hours of downtime, i found that coolant was seeping around the thermostat housing bolts and into the threads(nicked gasket)!?!? Anyway the lower intake manifold bolts should be torqued to 1 ft. lb. shown in the sequence found in the link below, and the upper manifold bolts should be tightened to 24 inch lb. also shown in the sequence shown below.(Sequence numbers are shown in boxes)

http://www.autozone.com/images/cds/gif/large/0900823d8015dfc1.gif