Thread: Coolant reservoir has brown junk in it and low coolant light flashing. what is it?

Went to go to the gas station tonight and when i turned the car on the low coolant light started flashing. It hasn't done that at all today. It is always kept filled. I just had the ac compressor fixed yesterday. I opened the coolant reservoir and there is this... brown stuff in it and it looks like it is sitting on top of the green coolant. There are little bubbles and you can see the green under them. Anyone have any idea what it is? I have never had this problem before. My radiator does have a small itty bitty leak. I know they are not the best pics but I am trying to figure out if it is oil or possibly rust or god knows what. The pic of the paper towel on the tip is what it soaked up from the reservoir tank. And sorry the pics are not the best, took them on my cell. I checked the radiator cap and on the underside of it seemed to be oil. Could the place i took it for repair screwed it up when changing out my ac compressor somehow? The car is a 2000 pontiac grand prix GT. I am at a complete loss

The GP is a 2000. I have always put in green coolant so not sure if it would be dexsluge. I have been putting green in it since i bought it in 2011 but I am not sure what the previous owners put in. I hope i haven't been mixing it this whole time if it is dexsludge :/

Also I forgot, when I checked the radiator itself, it was plum full of green coolant. Whatever this is, it seems to be sitting on top of the coolant in the reservoir tank only. And in the some of the pictures you can kind of see where there are like air bubbles and see the green under it.

Went to check it this morning and start it, there is a white exhaust coming out of the driver side tip, not a lot but it wrecks of gas. And forgot the cars SES light prior has been coming on and off did it like... eh 2 times trhowing a P0404- Exhaust gas re circulation Circuit range/performance. Not sure that has anything to remotley to do with this or even what the SES light is going to read now as that was from maybe like a week or more ago.

I will end up having to get it towed just to flush it and change it out since I live in an apartment complex and honestly don't want to even drive it because it doesn't even sound right and with the little bit of white exhaust coming from the muffler and the god nasty gas smell that comes with it.

New coolant tank at the dealership is like $15

So it seems to be a coolant issue then. I could deal with it just being a coolant tank issue. Would there be the possibility of a blown head gasket?

Originally Posted by JessicaRebel

I will end up having to get it towed just to flush it and change it out since I live in an apartment complex and honestly don't want to even drive it because it doesn't even sound right and with the little bit of white exhaust coming from the muffler and the god nasty gas smell that comes with it.

burning coolant almost smells sweet, check your oil dip stick make sure your oil looks good, could pull plugs to see if one is not like the others,
probly dex cool

open the rad and see if the cap is full of brown snot. then top it off from the rad, not the over flow tank.

looks like dex sludge to me, a coolant flush should fix it all. dont think the tow truck is needed. tell them to put green coolant in there.

I will go out and check it, I know last night the rad. was completely full of green coolant. The oil is dirty and low but it needs an oil change that was supposed to be done today. It's what I call its typical low from being driven. Ill pull the plugs to see if they are good or if one isn't like the others.

It does not pay to live in an apartment complex, cant do anything here. Ill be back with results.

i hear ya on apt living, it sucks for doing repairs. im always at my friends house doing work, or in a public parking lot lol ive done a lot of work in the stop and shop lot here by me, p/s pump, brakes, tune up and the list goes on lol

Yeah it does almost everything car related has to be done somewhere else lol.

So I looked there is no brown snot on it, just what looks to be black crust, it smelt like oil


Inside the Rad. there seemed to be a little bit of brown right on the inside like right above the coolant but not much at all. cant really see it in the pic but i mean the coolant is bright and green. Like it should be


On this paper towel the little bit of brown is what wiped off ( from what i mentioned above about the brown stuff.) The black is from the cap, and from trying ti wipe the inside of the rad

that all looks fine to me. the low coolant sensor on the rad maybe dirty and need a cleaning. when dirty they will make the low coolant light flash.

Ah ok I will have to get that cleaned. Would this cause the car to puff out the tiny bit of white exhaust i mean it almost looks like steam but smells to high heaven of gas, you would think I was dumping gas on the side of the car.

not sure on that. most cars will puff some steam out the pipes from left over condensation in the exhaust pipes. all cars get this, if you ever noticed a small puddle under your mufflers after idling parked for a bit. thats the condensation leaking out the pin holes that are in the mufflers. as the pipes heat up, the water burns off.

if your smelling raw gas, id be looking for a leak somewhere.

it seemed to stop real quick after i let it run for like a min. so im guessing from the cold. I am wondering if the stop leak for radiators i put in it did this... gonna go flush it crossing my fingers lol

where was your coolant leak? id not worry about the stop leak unless your running hot.

id let it be for now. if it starts to leak again, its time for a new rad.

stop leak aint always the best idea, some hate it, some dont think its all that bad. as long as your not over heating or running hot due to some kind of blockage you'll be fine.