I bought the approved stuff when I first acquiredthe tourer. It stayed the right colour for about a year, but the pipes front and rear of the engine are iron, not aluminium and have got severe signs of perishing, I cut back piping and replaced when the edges got very sharp.
The heater matrix got bunged up and since the aircon hasn't worked from day 2 I didn't bother to check too carefully until the antifreeze was black.
Draining and flushing over the next few years has brought out a shedload of rust, much of it from the heater matrix (lately using a pressure washer from either side of the hose inlets so I believe it is now clear of debris)
The thermostat packed up a couple of years back so I took it out, ran for a coule of seasons then replaced it three months ago. No change to daily running at all.
What I suspect is the root cause of the odd overheating during a long run is a build up of sludge in the engine block that just won't shift. I could put something corrosive in there but am reminded of the 'aluminium components' warning, so currently she has nothing more than tap water every week or so to top up and I stick to no more than 70mph for about ten minutes when I need to overtake.
I did try potted/condensate water in March (to ***ist with debriis removal) but all it did was make the water pump squeak so I stopped that. Putting washing up liquid in there just makes the system tiresome because of the bubbles at the bleed points
So, on long runs I stop every hour when the gauge looks about to pass beyond half way (forgot today so had to stop on the M25 and open the radiator cap to let out the steam.
Plus I carry about 5litres of water in bottles to give her a drink each time she protests.
Btw she's not burnt any oil at any time since I got her and there is no bloom in there so I don't suspect the head gasket is at fault,
