Brown "goop" in coolant reservoir
 

While draining some coolant to install thermostat I noticed a brownish tint to coolant. Also the plastic coolant reservoir has a residue of a slick brown film on the inside top and sides. Oil is clear with no signs of water contamination and the car dosen't act like a leaking head gasket so where's the brown stuff coming from? Am going to flush system and fill with new to see if this was an old problem or current. Just bought car, past owner could have added something to coolant or mixed in new type with old.

Thanks :confused:

Re: Brown "goop" in coolant reservoir (Five Window)
 

Time for a flush...

mine is currently like this... even have that slime around the radiator cap too :(

the last time it was like that I just had some boddies flush the whole thing for me and run some of that radiator cleaner through it.... cleaned it up nice... then i started putting only water in it (due to another issue which was fixed) and just from the water, it's startijng to get nasty brown again.... i just went and put a gallon of coolant in it again to hopefully help clean some of that up....

make sure you keep a good mix of water/coolant in it, as the water just messes everything up and corrodes and stuff...

Re: Brown "goop" in coolant reservoir (GIJoe)
 

I think you guys are seeing the (some) residue from the stop leak pellets that GM tells their techs to use. They are told to use it anytime the cooling system is serviced or opened. I personally don't use it because I want to know if I have a leak and I'll fix it properly but the General says to use it because of the problems with aluminum vs steel situations all over our engines .......... just clean it and flush it but watch for leaks and keep your smeller working looking for signs of hot coolant :seeya

Re: Brown "goop" in coolant reservoir (Five Window)
 

Depends on who you ask. Some swear that it's a blown head gasket, and the color is from the oil. I don't swear by that, but would check EVERYTHING out as well as I could. Check for white residue at the top of the dipstick, this is where the steam would collect if it was a bad head gasket. Also in the valve covers and around the filler cap, it's a gooey sweet smelling sludge you'll see if the head gasket's been bad for awhile. Personally I found that my water, tap water, gives way to this in my coolant systems. I have hard water, no softener, and it's full of minerals that can actually react with the coolant and the motor internals to create such a disaster. It had to do this a few times in other vehicles for me to understand this. That's why I use distilled water in all of my vehicles, and no more sludge! Good luck, hope this helps! :seeya

Re: Brown "goop" in coolant reservoir (93TorchRedC4)
 

hrmmm mine could be some kind of gasket... it has a VERY small leak under the intake somewhere above the waterpump... i was told by a vette shop it was a seal there and that i REALLY need to watch it and if it gets worse then i need to pull the whole top of the motor off and reseal it or something... hrmmm... perhaps thats what im seeing in mine...

Re: Brown "goop" in coolant reservoir (Five Window)
 

Yep, I had some of that goop in the reservoir also. I cleaned it out thouroghly when I had to replace a radiator hose. I removed the whole reservoir to make sure I got it all. The coolant I drained did not seem overly dirty. I was wondering if it was a product of the antifreeze itself. I don't ever seem to be down any oil, but I had that thought (head gasket) as well.

Ken


[Modified by rockken_vette, 1:56 PM 10/15/2002]

Re: Brown "goop" in coolant reservoir (rockken_vette)
 

Well if you definately have a coolant leak by the intake my vote is as before ........the GM pellet........ been there .........seen it......... don't like it but that's the way it is........... Might want to pull the intake for some new gaskets........ you'll love that job!!! :seeya

Re: Brown "goop" in coolant reservoir (Five Window)
 

Thanks for the info, especially about the GM goop. I'll flush the system and keep an eye on it.

Re: Brown "goop" in coolant reservoir (Five Window)
 

Mine was yeechy (technical term) when I pulled the radiator to clean it.
I let mine soak in 50% bleach and water to clean the crud out of it.
Its probably the pellets or something like that. My fluid was a nice green (anti-freeze) color when I drained it so I knew I didn't have any real problems hiding.

Like other folks said, use distilled water when refilling. City and well water can have all kinds of wierd stuff in it that cooling systems don't like.