Draining and Re-filling Coolant

[RoadWarrior]

I'm going to attempt draining the coolant system before the really bad weather hits and wondered if anyone could point me in the right direction.

 

 

1) Where is the best place to drain it? Is there a plug on the radiator somewhere or is there a better / easier option?

 

2) Once drained, is it worth sticking a hose in the bottle (with the plug still out) and flushing it out for a while?

 

3) How much mixed coolant needs putting back in? (i.e. 50/50 mix of AF + H2O = total litres)

 

4) Will this be suitable: http://www.halfords.com/motoring/engine-oils-fluids/antifreeze/comma-g30-antifreeze-and-coolant-rm-5l

 

 

Thanks in advance

[Chan110]

Interesting topic - i like to know too :-)

[mluton]

Facing front onto the car the radiator tap is on the right underneath the bumper, you can see it, feel it, just turn and drain. Lots more cam out when I removed the thermostat after the tap ran dry though.

 

I used 50/50, but used proper skoda stuff. 2 bottles mixed.

Edited 2 December, 2014 by mluton

[IulianE]

you will drain a bit more than half of coolant capacity,only the radiator plus tank and hoses .You can't drain the engine,there is no plug

Ideally is to do this when replace the water pump to drain the engine and radiator.I drained exactly 5l of antifreeze from engine and radiator

And you better use propper G12 antifreeze.

Edited 2 December, 2014 by IulianE

[RoadWarrior]

So it won't drain it completely... but what if I put a hose in the bottle and blast it through? Ideally I want to get all the old coolant out.

 

I can only find the G13 stuff - is that ok or does it have to be G12?

[mannyo]

IIRC G12 is no longer available and has been superseded by G13.

 

You cannot mix certain coolants, so even if a small quantity remained of the old coolant, mixing in the wrong one can cause a chemical reaction which damages seals and other components. G12 and G13 can be mixed, so no problem on that score.

 

Have a read of this thread for more info, on vwaudiforum

http://www.vwaudiforum.co.uk/forum/showthread.php?137649-VW-G13-coolant-ready-to-use-or-dilute-Ok-to-mix-with-G12

 

Hose in the bottle will not do a lot to get the remainder out, it will just go through the hoses and radiator and not the engine.

[RoadWarrior]

Hose in the bottle will not do a lot to get the remainder out, it will just go through the hoses and radiator and not the engine.

 

That's confusing though. If I managed to completely drain it (ignore how) and then went to fill it back up again, by putting coolant back in through the bottle... then again, that would only reach the rad and hoses.

 

So then how do you fill the engine? :S

 

 

Surely there is a way to completely drain everything and completely re-fill it without taking half the engine apart?

[Simeon85]

When you warm it up the thermostat opens and allows water through the whole system. This is why you have to get it warmed up, let the fan kick in then switch off and top the water up as required.

 

Not sure if this is the case on an Octavia, but on my last Audi the thermostat had a small hole in it that did allow the water through (albeit slowly) so I imagine if the thermostat is designed like that, if you let it drain over night then most would come out.

 

Removing the thermostat would ensure 100% drainage  I wouldn't recommend going to the trouble of removing your waterpump to just replace the coolant.

Edited 4 December, 2014 by Simeon85

[IulianE]

The 100% drain is not possible on any fluid.

If you want to be an perfectionist,wich is useless if you ask me I recommend you another method.

Drain the radiator and then flush the sistem with alot of water ,so what remains in the sistem will be cleam water....then add atifreeze and check the freeze point during the adding process.

VAG manual recommends using tap water.

[kentphil1]

That's confusing though. If I managed to completely drain it (ignore how) and then went to fill it back up again, by putting coolant back in through the bottle... then again, that would only reach the rad and hoses.

 

So then how do you fill the engine? :S

 

 

Surely there is a way to completely drain everything and completely re-fill it without taking half the engine apart?

I suppose you could pull the stat out, but it seems a bit extreme in this temperature outside at the moment - recipe for nothing but a bad attitude at the end of the job.