5kkm ago I filled LHM tank with Hydrorincage. It is a amber coloured flushing fluid made by Total. I do not have reliable data, but it closely resembles LHM. Most likely it is the same mineral oil with special additives. I also read somewhere in forums that it can be filtered and reused. Will look in to that. As far as I know, it is intended to wash system when it was contaminated by foreign fluids (engine oil, diesel fuel, etc.). As I did not know how my BX was serviced before me, I flushed it anyway to have a fresh start.
Prior to filling mentioner liquid I washed filters and LHM tank. I also dropped a magnet in to the largest filter housing to which operational return hose is connected. Here is how magnet looks like now:
Small plastic cap on the left is a bottom lid from level gauge. I was laying at the bottom, but I assume it dropped when I removed LHM tank lid. It is not clear to me why it is full of gunk. Otherwise filters were clean, only a few larger particles and no gunk.
Hydrorincage after 5kkm became green and opaque:
I suppose it simply washed some of the green pigment from piping and became green.
I cleaned LHM tank again. First it was wiped “clean” with a towel and then rinsed with some rubber solvent petrol (Nefras, oil distillate from 80-120 °C). Picture below shows how much dirt “wiped clean” tank still has.
And thats how fresh LHM looks like:
Now when system is flushed I hope to do something with leaking flow distributor valve (FDV) and sticking height correctors. They might have collected some of that contamination fluid has lifted.