I tend to use distilled water (salvaged from my dehumidifier) for the engine cooling. Might be brown from the heater matrix, although I did quickly flush it out. I'll probably drain down again, and try again. Thanks Gents.
On the SAOC forum there is just posted that 1/3 of blue anti freeze plus 2/3 of distilled water is the solution to avoiding that this mixture is getting dirty. The poster has tested this on his Alpine for some time and it seems to work.
It could be as a result of what was left in the heater matrix: a lot of debris sit in here, but cleaning them out can cause leaks! I always used Bluecol in 'the old days', but my mechanic mate preferred the green BMC-type stuff of the day. I now use one of the modern-type orange coloured ones in my car & haven't found any problems; but yes the water is still a bit rusty again even after a fairly major drain-off to do the head gasket. I always keep a 50/50 solution or even stronger to help keep corrosion at bay. Cheers. G
I stripped my 1725 engine and replaced the camshaft, checked everything and thoroughly cleaned the water galleries. The radiator was re-cored at the same time, and when all re-installed filled with 50/50 anti freeze and water. After just a couple of thousand miles the water is very rust coloured and dirty. Have I used the wrong type of anti freeze? Is there a strong recommendation of type for these engines with alloy heads?