So, my car overheated today. I look to see how is the coolant level and theres this weird, brown, gunky, slimy, substance in there. Anyone know how this happens and how to take care of it?

 

sounds bad.

oil in rad fluid. headgasket is your cheapest and easiest solution. if its not that, you have a busted engine.

 

well, i spoke to a mechanic and he said to flush out the radiator first, cuz it could be that i used another type of coolant different from the one that was there and that caused a chem reaction that makes that gooey stuff. it really doesnt smell look or feel like oil so i hope he's right.

 

have you always put the green stuff in? or did you perhaps buy the red stuff (bottles usually say something like "Last 100,000 miles" or something rather. Some engine/radiators (like the Chevy Blazer) were designed to use that kind of coolant but tibs only use the green stuff. change/inspect every 30,000.

 

GMs and such were designed to run on the Dex-cool (pinkish-orange coolant). Dex-cool and the standard green coolant should be compatible. The last time I bought coolant a month or so ago the green Prestone said it worked with either stuff. When combined they should not become a brown gooey mess. Give it a flush & change and pray.

Inspect often and change at least every 30,000 miles

 

I never updated this topic, the problem was that the head cracked and the oil and coolant/antifreeze was mixing. The solution was to get a new head but my mechanic found a replacement engine. Mine had 115k, this "new" one had 52k. Apparently the donor car was in a rear end totaled accident. With a new engine+new clutch+new engine mounts+new tires, the car rides super smooth now.

btw, that brown gunky stuff, it looks like chocolate shake. I'm just writing that for future reference.