I have a 03 chevy impala with the 3.4l in it with 90,000n miles...today when i was checking fluids i noticed brown gunk on the radiator cap..it dexcool in it..i then checked the oil fill cap and that

What is your question? You should not operate a vehicle that overheats. You should not put just plain water in a cooling system for a car. You can see the leak? You should get it fixed before any more damage happens to the engine. Failure to keep the engine cool can cause a host of problems and none of them are cheap to fix.

The adding adding coolant means you have a leak somewhere, and low coolant level will cause this. How often do you check the fluid levels? Check for leaking hoses, weak radiator or expansion tank cap, leak at the water pump, and leaks around the radiator.

have a coolant system pressure test done to check for the leak. Check directly under the water pump as there is a drain hole there for when the pump seal fails. The brown stuff may be rust from an engine on the point of overheating.

It probably won't get any worse than it is now. Sealer is supposed to plug leaks when it comes in contact with air. Otherwise it stays suspended in the coolant.
You may want to do another flush in 6 months and then just keep an eye on it. Make sure the radiator and overflow tank are both full of liquid coolant.

Try changing the tempature coolent sensor first it may have got gunk on it when you got the system flushed and if that dont work you should take the radiator out and have it profesionally cleaned to take all the gunk that could be clogging up the blades inside of it and not letting air cool the fluid if that makes since to you.. if you have any more problems just ask away

Brown gunk is either oil from a blown head gasket or 'stop-leak'. The head gasket is expensive to fix.

If you have over 150,000 miles probably cheaper to replace the car if the head gasket is bad.

GL,
Td

check heater core

more than likely but if the temp gets to high you run an extremely high risk of blowing a head gasket or warping or cracking the head.So have it changed out before driving the car much more and also have the water pump checked.

how can i take of a power stering from impala 03

I have replaced the radiator in my 2003 Chevrolet Impala LS. The car started running hot and shut down. Took it to a radiator shop and found a crack in the radiator. I have replaced 2 thermostats in the car already. I noticed water running from under my car today and it seems it was coming back out of the overflow. I am stumped as to what is going on with this car.