Brown Slime in radiator

[SuperMario92]

Ok, so my gf's radiator has brown coolant and it's kind of slimy. We discovered it when she said that her car all of a sudden started leaking 'brown liquid' and then quit leaking. The oil level was ok so, I checked the radiator and sure enough it's was the coolant. Here are the facts

1: The leak was never found, and it's no longer leaking
2: She had an overheat condition some time ago took the car to a mechanic and he supposedly swapped out the rad.
3:The car is not overheating and hasn't overheated since the had it 'repaired' last fall.

Here's what I'm thinking. This asshole never actually did any work on the car and the rad was not the cause of the overheat. Or the car had a pinhole in the hg and he used some steelseal and by miracle it worked but, now I wouldn't want to drain and fill the rad in case that's what's keeping the car alive. Or he actually did the work and but mixed red and green coolant (I read online that might do it) or he filled it and some other gunk got disloged over time.

Should I swap out the coolant with fresh stuff? I'm thinking that what I should do, right?

 

[harrycalahan]

Does the rad appear new like he installed one? Ya drain it and run some water through it and keep flushing/driving until clean and throw some antifreeze in and hope it doesnt come back. If its an automatic the trans cooler could have sprung a leak in the rad. Beware of soft hoses if you've been driving it like this for a while. Petroleum rots rubber.

 

[galvatron]

Combination of rust, stop leak, burnt nasty old coolant and maybe mixed coolants. None of which are good. You need to drain the system and flush it a few times. Then refill with correct coolant and see what happens.
Or just ignore it....

 

[Mirvin 264]

If you add the "Bars Leaks" pellets to a leaking radiator or gasket you will see a brown slimy residue in your overflow tank and under the cap at the top of the radiator level. It is the brand with the bb size pellets suspended in what looks like molasses. I had a leak at my head gasket, put a bottle in and the leak stopped the day after I added it. Left the brown residue but did the trick!

 

[SuperMario92]

Does the rad appear new like he installed one? Ya drain it and run some water through it and keep flushing/driving until clean and throw some antifreeze in and hope it doesnt come back. If its an automatic the trans cooler could have sprung a leak in the rad. Beware of soft hoses if you've been driving it like this for a while. Petroleum rots rubber.

Combination of rust, stop leak, burnt nasty old coolant and maybe mixed coolants. None of which are good. You need to drain the system and flush it a few times. Then refill with correct coolant and see what happens.
Or just ignore it....

Yea, it doesn't look healthy at all. But, it's the see what happens that scares me.. if the mechanic skimped out and put some pour in miracle cure, then I come along and flush it, can I make the overheat condition reappear?

I don't know if it looks like a new one. I'll look tonight and see if there are any factory stickers or dates.

 

[SuperMario92]

If you add the "Bars Leaks" pellets to a leaking radiator or gasket you will see a brown slimy residue in your overflow tank and under the cap at the top of the radiator level. It is the brand with the bb size pellets suspended in what looks like molasses. I had a leak at my head gasket, put a bottle in and the leak stopped the day after I added it. Left the brown residue but did the trick!

How long did that last you?

 

[Mirvin 264]

How long did that last you?

I had a quote of almost two grand to replace the head gasket on my Mazda pickup. It was just a slight leak but I figured it might get worse so I added it back in the spring of this year. I commute 122 miles a day to Atlanta and back and I have not seen a leak since then. I have close to 200,000 miles on my truck and the pellets have done the job so far. My coolant is still good (used the 5 yr./150,000 mile version) and looks pretty brown on the surface but it's more than likely just the residue from the liquid suspension the pellets come in. No overheating problems and the company claims that it also helps lubricate your water pump. I have heard in the past that manufacturers run this material in new vehicles if they develop a leak before going out on the market for sale but can't confirm this. All I can say is that I have used it in two of my vehicles and it has worked both times..............

 

[Jeddak]

What make and model car? What's OEM coolant? "Brown stuff" could also be Dexcool when it is exposed to air.
Bar's Leak is a good stuff. Subaru requires adding it to their cars, during coolant changeover. Subaru boxer engines are prone to headgasket leaks. It is a shredded tree root.
Do you have any coolant in the oil? Look for milky residue. You can also pick up an oil analysis kit from Amazon for under $20 and send oil for analysis. They will be able to tell if there are traces coolant in the oil. One of the labs in in Atlanta, so you should get results fast.
Leaking transmission radiator is another possibility. Check tranny for high fluid and signs of coolant, same as oil.

Replacing coolant with fresh staff will not "flush out" the plug, if Bar's Leak was added. If in doubt, add some more, but go by the bottle recommendations, do not dump the whole thing in. Do not use All Makes/All models coolant. It is a Dexcool clone and should not be used in non-Dexcool cars. 2EHA acid it uses is nothing to play with. BTW, draining radiator will replace only 50% of the coolant in the car, so you will need to do it 3 times to get most of the old stuff out. I normally drain the radiator, fill up with distilled water, run the engine untill it is hot, with heat on to work the heater core and do it free times. drain, fill up with straight coolant (50% of the system capacity), run to mix, same as above and test the concentration with hydrometer and coolant level overall. If you are at 50/50 mix, but low level, mix up a 60/40 top off bottle and use it to fill to level.

 

[georgia357]

I had a quote of almost two grand to replace the head gasket on my Mazda pickup. It was just a slight leak but I figured it might get worse so I added it back in the spring of this year. I commute 122 miles a day to Atlanta and back and I have not seen a leak since then. I have close to 200,000 miles on my truck and the pellets have done the job so far. My coolant is still good (used the 5 yr./150,000 mile version) and looks pretty brown on the surface but it's more than likely just the residue from the liquid suspension the pellets come in. No overheating problems and the company claims that it also helps lubricate your water pump. I have heard in the past that manufacturers run this material in new vehicles if they develop a leak before going out on the market for sale but can't confirm this. All I can say is that I have used it in two of my vehicles and it has worked both times..............

I had the exact same thing in my Mazda pickup. The stop leak on mine lasted about a year and then had to put some more in. Done this for about 4 or 5 years and truck had over 240,000 miles when I sold it. As the OP, my water looked like brown gook, but it didn't run hot.

 

[Tony2X]

It aint broke so don't fix it.