Bleeding system - was Coolant flush method?

[Cruz]

Being a lazy a*** I can't recall ever changing the coolant on a car or the van myself which is a bit embarrassing considering the other things I have done to the van.

I am changing a heater pipe before it holes so I am going to change the coolant ,as it's due, and replace any crusty looking jubilee clips. Should be fun on my back

I have looked in the wiki and whilst there is a plethora of information on coolant types, specs and system bleeding there is didly squat on flushing the old coolant out.

Which way would give me a decent system flush ready for some new Comma blue coolant?

Is it an ok method to remove a pipe (which?) then flush system out with hosepipe in header tank???
What about getting beyond the thermostat?

By the way if it matters 1983 1.9DG

[fix]

Ive just flushed mine out before I put new stuff in (cheap 2 year stuff as G12+ cost me £50 last time and was only in a year!)

I think its best to flush the system both ways.

I took the hose thats at the right hand side of the engine bay that attaches head off (furhest away looking from the back of the van) and took the hose that goes from the thermostat housing to the front of the van off. Flushed both ways with a hose pipe.

Didnt bother with the header tank etc as the engine had been out awhile there wasnt anything left in it, but I guess aslong as the coolant can escape you could attach it anywhere.

[Cruz]

I removed my front to back pipe connections to replace rusted clips as well as the heater pipes. Flused them out and the engine block but I only managed to get in the 8 litres of coolant plus about 2 litres of water.
Does that sound about right as there's supposedly 17 litres of fluid in the system?

Bubble free coolant from rad bleed screw after bleeding and temp gauge sits merrily on half way. Going to give it a second bleed just to make sure today

[fix]

No that doesnt sound right!

There is about 17 litres of mixed coolant on total, I got about 15 litres in the other day then had to mess about abit to get the rest in.

There must be some air trapped somewhere, I assume not in the radiator.

Have you trued undoing the bleed screw ontop of the thermostat housing? If you undo it be careful they can be abit flimsy.

[Cruz]

Mine is a very early engine bleed screw that has a mangled screw slot so cannot be opened. The temp gauge sits in the middle.

TBH I flushed the engine block and emptied the contents of the front to back pipes and 1 van length heater pipe. There assume must still be quite a bit of the old coolant that I didn't get out?

If not what else can I do to find where the air is trapped?

E D I T: According to the wiki bleeding page flushing the system from the lowest point leaves about 6 litres of water in the system. So 6 + 8l of anti-freeze = 14 and I put about 3 litres of water in too so maybe all is well after all?

I'm going to re-bleed on a slope just to make sure