I went through the thread link above. To me, that looked like the same results of the oil cooler leaking to the coolant problem I had. I would agree that it was oil, however, red and green does make brown, so mixing coolants???Maybe??, but the thickness and slime looked like oil to me. Even after the repair, I am still getting residual oil in the coolant bottle. I keep sucking the oil from the top, when it gradually accumulates and floats over time. It is not nearly as bad as before the oil cooler change. Before, it was the entire coolant bottle that was sludgy and brown, now it is just an occasional thin layer on top, with nice green fluid below that film. The mechanic said to expect this, since there will still be residual oil in the cooling system, deeper than he can get to without getting into a much bigger project. Part of me thinks there is still another problem somewhere else in the system.
I am not nearly as experienced as others who offer their advice on these forums, but isn't there also issues with wrong coolants incompatibility with hoses, gaskets and seals among manufacturers?
Makes me wonder, did the oil cause your issue by deteriorating your o-rings and gaskets, or did incompatible coolant cause the deterioration of the o-rings letting oil in?
When I had my strawberry milkshake, I first did several coolant flushes after my repair until I was confident there was no more ATF contamination in areas that were hard to reach and also not contaminate my new hoses with residual ATF fluid in the system. I had already replaced the heater core before this problem, so I was not going through that again, but hoses are easy to change and not crazy expensive. Peace of mind to replace the hoses and peace of mind that the flushes got rid of remaining contamination in the lines, block and core before putting on new hoses.
