How can I PROPERLY flush the coolant system??

[CelticPixie]

Hi,

With a recent broken radiator thermostat housing, I've got three plastic bits 'swimming' around inside my coolant system. (2004 Dakar)
The pieces are about 3x7x1mm each. I've taken the radiator out but haven't found ANY of the three pieces... and I'm now worried they might block my waterpump AGAIN in the near future... or maybe something worse – I don't know. (I've just replaced the waterpump gears and seals / shaft).

So:
How can I properly flush the system, particularly inside the engine / around the cylinder head? Should I do it with engine running, or can I do it switched off?
Also: Is there some sort of "filter" or narrow passage inside the head, where the pieces could get stuck and cause further/severe damage? Can I flush it "against the current", i.e. from the right hand side of the engine TOWARDS the waterpump, in case there is some sort of filter / narrow passage?

As for "tools" I've only got a garden hose, and the water that comes from it looks somewhat "milky". Better to tow the bike to some better water-quality?? Or would ne anti-freeze/distilled water take care of that?
I'm a bit worried about continuing without finding all the pieces, as the next 1000km will be in extremely remote parts of Bolivia, on bad dirt roads without much traffic/road assistance options I believe...

Thanks!
CPixie

 

[komatias]

Mate,

I would definitely use the garden hose in the opposite direction. The smallest passages are unfortunately in the head itself so make sure you get alot of pressure. The bits you are after are thus in the heads water jacket.

Keep the head bleed nipple closed as you don.t want the particles being flushed in that direction.

It is probable that the bits got stuck in the waterpump snail and that caused your gears to fail.

Once you are happy with the flush , lie the bike on either side to remove the remaining water inside and then fill up as normal with water and antifreeze. Or even help the flush with gravity by doing it all with the bike on its side.

Do not even think about running the bike without any coolant. It get very hot very quickly and you will do more damage.