Complete Coolant Drain 6R?

[JiSingh1]

Hi all,

First post.

Bought a Polo 6R, & have realised the engine coolant has been filled with pure water it seems. Has been a few months like this, so i am wondering what's the best procedure for a full drain?

I have access to a ramp so can get under the car. I know I can remove the lower radiator hose & open the lid on the coolant tank, and drain it that way, but will this remove all or nearly all of it? I want it to be realistically be a full flush so I can add some G12/G13 coolant to the tank.

Thank you all
Ji


Sent from my iPhone using Tapatalk

[veteran]

JiSingh1,

Someone here might correct me if my memory's off about this but I seem to recall seeing in the Haynes manual a drain tap incorporated underneath the vehicle, in the case of the 6R. If it's truly a 6R (2009 - 2014) you've got then to look for that drain tap. Otherwise, as you say, you'll need to do it by disconnecting the lower radiator hose, with the tank's lid removed. Either way, a small quantity of the coolant might still be left in the system.

You describe the current coolant as "pure water". Do you truly mean that, or do you just mean "what looks like ordinary tapwater, with little or no colour to it"? Either way, you'll need to dispense with what's in the system (as far as is possible) and re-fill with the proper and recommended VW coolant, made up to the concentration to give you the requisite engine protection. With G12/G13, offhand I can't recall the concentration-level normally used (at least, for winters experienced in the UK); I think it's 50%. If a driver's handbook came with the car, look in it to find out the concentration level needed. The G12/G13 coolant therefore comes as a high concentrate and before you re-fill the system you'll need to dilute some of it with denatured water, to give you the system concentration required. That's to say, you'd use some de-ionised water to dilute it. You can buy de-ionised water in litre cartons at petrol stations and in some supermarkets; it's inexpensive stuff; some would refer to this as pure water, or even distilled water. Hence my earlier question. There'll be a tendency for the system coolant to lay down calcified deposits in the engine's coolant galleries and water pump if instead you use ordinary tapwater.

Note that the made-up concentration of the coolant can, if it's significantly off, affect the efficiency of the engine and the rate at which the warm-air system, inside the car, heats up in the winter. Although maybe not as significant in the case of a 6R as a 6C, that coolant is therefore not just a general-purpose absorber and conveyor of heat, it's a specially-developed solution that plays a part in the fine tuning of the engine.

I once adjusted the concentration on my 6C (without wishing to drain the entire system). In the case of the 6C there's definitely no convenient tap down below, so in that particular case (where I wanted to take out just a few 100ml) I had to use a clean turkey-baster to suck that amount directly out of the tank. I then found that adjusting the mixture was quite tricky to do, as it wasn't simply a case of making up one single lot of the coolant and just pouring it into an empty (or near-empty) system, it was a matter of carefully blending the remainder in the tank with a replacement concentration different to the resident one, sufficient to accurately re-fill it, and such that the net concentration (after running the engine) was what I'd aimed for. What helped me get the net concentration absolutely spot on was the use of a small portable refractometer (you can buy these online and they're handy for adjusting/checking windscreen-washer fluids as well) . It took the guesswork out of the exercise. Far better than messing about with a hydrometer that, in any event, would likely give a false reading.

[JiSingh1]

Someone here might correct me if my memory's off about this but I seem to recall seeing in the Haynes manual a drain tap incorporated underneath the vehicle, in the case of the 6R. If it's truly a 6R (2009 - 2014) you've got then to look for that drain tap. Otherwise, as you say, you'll need to do it by disconnecting the lower radiator hose, with the tank's lid removed. Either way, a small quantity of the coolant might still be left in the system.

Well, i looked at a Youtube Video of someone draining a 6R coolant, and they said there was not a drain tap and that it requires you to disconnect the lower radiator hose, was hoping someone with a Haynes manual could check for me, not sure where else to ask. I know i can drain most of it by opening the Engine coolant header tank lid and disconnecting the lower radiator hose, then start the engine to try push out any more if i am correct.

Would it be ok to leave the lower radiator hose off and blast some water through the Engine coolant header tank to try push out any possible deposits?

When i say pure water, i believe it is just filled with ordinary tapwater from what i can tell, and as you say it can lay down calcified deposits so need it changed really. Euro Car Parts sell Triple QX Purple which it says is pre-mixed and conforms to VW G-13/TL 774J standards, so i could just use this, right, to make it easier? However the header tank does say G12.

I could use a refractometer, whatever that is, lol, but i think if i use pre-mixed and try drain most of it, i should be ok.

Thank you

[veteran]

On p.1A-15 of the Haynes manual to which I referred there's a photograph of the coolant being drained off using that built-in tap. It looks to be part of the large lower hose at the radiator. I suspect that VW may have fitted this tap to only certain models of 2009 - 2014 Polos, or in certain years. They may have then given up incorporating the tap, perhaps as a money-saving exercise or because it made that lower hose difficult to manufacture. But if it's there on your 6R, you'll need to look for a small rubber spout and big plastic hex nut, sticking out from the main lower hose, a few inches in from the front of the vehicle.

If you intend running the engine in order to drain off the last remnants of the coolant be aware that heat will build up very quickly and you may run the risk of the water pump bearing seizing up. I personally would not do things that way, particularly because once the engine is running you'd then lose control of the emptying. I somehow doubt, in any event, that you'd succeed in getting the very last drops out. I'd reckon that the only way you'd do that would be to remove the water pump. I would also suggest that "blasting" water through the system from the header tank is also likely to be fruitless, as you'd be trying to force a comparatively wide stream of water through a narrow orifice (the tank's exit port) at atmospheric pressure; even if it worked to some degree, you'd run the risk that any crud left in the system would be pushed eventually into the water pump, jamming it up.

As for the precise type of coolant, you may have to do a little background research to find out if G13 is a suitable replacement for G12. Is G12 still available these days, I presume it is? ECP's products are usually dependable, so if you can confirm that ECP's G13 is compatible with your engine and pump, then by all means go with that. My personal view is that I'd stick with what was originally specified for your particular Polo, and I'd buy the actual VW stuff. Do you have a Driver's Handbook for the car, as it'll usually state there the type or types of coolant that can be used? Do appreciate that certain constituents of the coolant are used to continually lubricate the water-pump's bearing.

[amer6R]

Well you can never drain 100%, but you can flush!