Foaming Coolant

[iamtall77]

I've read the few threads in this forum that deal with this issue. This is on my 95 TSi AWD. In short, my coolant is brown and foaming when the engine is warm. I don't seem to be losing any oil. There is no coolant in the oil and the compression on the cylinders is even across the board. (150psi @ 11.8psi atmosphere) My coolant overflow bottle had, what appeared to be, mud at the bottom of it when I flushed the system. I now have over 5 gallons of brown fluid and it is still getting discolored when I add new water to the system. What the heck is going on? I can't think of anything other than maybe a bad headgasket that seems to only leak between coolant and oil passages. Or that my oil cooler (stock) somehow is getting oil in the coolant, but not coolant in the oil. ANY ideas?

 

[iamtall77]

Two great suggestions were given to narrow down where the problem is. First, I'm going to drain all of the coolant (water) again and then disconnect the oil cooler lines. This should eliminate the possibility that oil could be getting in from the cooler. If that doesn't pan out, I'll push compressed air into the oil system and see if any bubbles appear in the coolant. Those are the only suggestions I've gotten, so I'll roll with that and see what happens. I'll post my findings here for others that may have this issue.

 

[iamtall77]

No go on bypassing the oil cooler. My car is also an automatic and I tried bypassing the tranny cooler too. neither seemed to do anything. I'm giving it a last ditch effort and throwing in some "head gasket repair" stuff. Not sure that it will work since the oil (or whatever) is getting in the coolant and not the other way around. I'll post any findings here.

 

[tsunari]

First of all . . . I'd flush the entire coolant system. Over time, coolant breaks down and turns acidic . . . then begins to corrode and eat away at the internal passages in the head (perhaps even the block as well).

So Flush everything out with some coolant flush (follow directions of course), then refill with new coolant/water mix and see what happens.

If the overflow bottle turns brown again after that, pour the liquid in a clear plastic bottle (used peanut butter jars are great for this) and let it sit for a while. If there is oil in it, it will separate and float to the top.

Get all of that done and report back We'll go from there . . .

 

[iamtall77]

Still have no idea what was in the coolant. I flushed it multiple times and ran straight water for a couple days. Still turned brown. I did find a brown substance in the bottom of my coolant recovery tank. Seemed more like mud than oil. I had a bucket that had about 3 gallons of flushed liquid and no oil floated to the top.

Whatever was wrong, it's fixed! I put some stuff called Bar's Leak Head Gasket Repair. Seems to have work. Or if nothing else, the long procedure you have to go through with this stuff flushed the problem out. Everything seems to be fine now. If it happens again, I'll report here.

 

[red_devil]

Over time your coolant will begin to break down and turn into this sludge. Try to flush your system every 3 years.

 

[tsunari]

Still have no idea what was in the coolant. I flushed it multiple times and ran straight water for a couple days. Still turned brown. I did find a brown substance in the bottom of my coolant recovery tank. Seemed more like mud than oil. I had a bucket that had about 3 gallons of flushed liquid and no oil floated to the top.

Whatever was wrong, it's fixed! I put some stuff called Bar's Leak Head Gasket Repair. Seems to have work. Or if nothing else, the long procedure you have to go through with this stuff flushed the problem out. Everything seems to be fine now. If it happens again, I'll report here.

Yeah that stuff just breaks down over-time . . . on a side-note, if that is some kind of leak-stop thing you added to your coolant, I would highly suggest flushing your system out again thoroughly.

That stuff is designed to seek out small cracks and seal them up long enough until you can get a permanent fix . . . just sit back and imagine what it's doing inside your CHRA.

Glad everything cleared up though

 

[iamtall77]

My guess is that it was just bad coolant. I drained and refilled the coolant last summer, but the car sat for 2 years prior to my purchase. So I'd imagine that there was some crap in the system that finally caused an issue. The thorough flush I did with that leak stop probably fixed it, not the actual leak stop. Didn't think it would work, but everything seems okay for now.