GTA V6 Turbo - advice on flushing the coolant system?

Just wondering if anyone has any advice - is there a best / accepted way of giving the coolant pipes / system a good flush out with the radiator off? The water that came out was rusty coloured so I'd like to clean out as much residue as I can without getting into a major engine overhaul.

The reason I've got to this point is that the original radiator was leaking so that is out and I'm now waiting for a new Racing Winner Chinese ebay special to arrive. With the front end exposed I'm sorting what I can:-

Renewing the 2 corner bumper supports - these were tatty and not bolted to the underneath of the bodywork so the bumper corners had dropped.
Refurbing the hoses, fans and renewing all connectors, bolts etc
Bitumen painting the underside.

Some pictures attached

While you are there:
You could try and get the Fuel filter higher up into the underbody of the car, it is known for them to get ripped off when going down country lanes with grass and mud in centre of lane.
Upgrade the orange indicator to clear, it makes the car look cleaner. There was a post about this in the last few days.
I choose to cable tie my bumper back on, saves all those bolts going rusty.
If the water is "rusty", there will be sediment in the block too. It collects in there too.
There is a plug one each side of the block, you need a square tool to screw it out. See WS manual page B-9. Mine both look like the item marked B. but the other is in position A.
1 is just above the oil filter and other is in same position on the other side.
Dont be surprised if you unscrew the plug out and no water follows. This is because there is a wall of sediment inside the block. Just pierce it with a screwdriver.
You can insert a hose into the block and flush through side to side till clean.
Also poke hose up central pipes while rad is off.
Just dont get anything stuck in there

You are half way there with the rad removed.
Next .... remove the two drain plugs, one either side of the block, they require a square ended drain plug key, and they will be tight. They will also need 16mm copper washers, the same as the oil drain plug when refitting.
Remove the thermostat.
Put a plastic bag over the alternator so as the water gushing out of the block drain does not enter the alternator. It might be wise to protect any wires and connectors on the inner wings.
Get a hose pipe with a trigger nozzle connected to the mains water for the pressure, and with rag wrapped around the nozzle to create a "seal", offer up the nozzle to each of the rad hoses in turn and fire the water up from the rad end until it runs clear from the block drains. If you do not remove the thermostat, you will not be able to flush from the near side rad hose.
Note ...... keep the reservoir cap in place whilst flushing but wash out the reservoir separately before you refill.
Once you are happy that the water is running clear, replace the thermostat and drain plugs, fit the rad and get yourself some Type "D" coolant from Renault ...... failure to use Type "D", then you have wasted your time.
For refilling, jack the rear of the car up to get an angle so the air will be pushed back up towards the engine and refill slowly. Once it is nearly full, bleed the rad, but you must remove the bleeder from the pipe so that there is a decent flow that will pick up the air and once you can see a clear flow, replace the bleeder.
Top up the reservoir .......... I am sure you know what to do from then on.
Tip …... Just one other detail ….... to help with the bleeding of the coolant circuit, you should notice that the original thermostat does not have a jiggle valve, it has been found that whilst you have the thermostat out, drill a 2.5mm hole in the top of the stat as per pic below otherwise there will be an air lock which can take some shifting. The hole will allow the air to pass slowly and ease refilling …... but take your time refilling. The coolant comes in 5 litre containers …... I decant it into a one litre container, this allows time for the air to pass through the hole.
The capacity of the coolant circuit is 15 litres ….. you may need a bit extra for topping up in the future.
I hope this helps.

Thermostat hole.jpg

Great advice, Simon and John....thanks to you both!

Also, I hear that car water cooling systems normally bleed them selves quicker if the cabling heater is set to Hot, which opens up this circuit.

....... I hear that car water cooling systems normally bleed them selves quicker if the cabling heater is set to Hot, which opens up this circuit.

Simon ...... none of the heater controls start and stop the coolant passing through the heater matrix ..... there is no coolant shut off valve ..... the only thing the heat control does is to is vary the amount of air passing through the matrix ..... for cold, it just shuts off the heated air output to the cabin.
There will be a small amount of air stuck in the heater matrix when filling, but once the engine is started, the coolant is forced through the matrix and back up to the reservoir.
John

Thanks for the details John, much appreciated. I was not sure for the GTA heater matrix, which is why I was a little non committal.

Update - new radiator received and fitted, ready for filling and bleeding, then bumper on.

I can't fault the rad supplier "Winner Racing" in China....ordered it through ebay on 14th Sept and it arrived yesterday - 11 days door to door! If anyone else is thinking of buying a GTA radiator, there are multiple offerings at different prices from Winner Racing but just select the cheapest (with P&P) because apparently they are all the same despite what the listings say!.

It's much lighter than the original, but same size, layout of the inlets, temp sensor, bleed pipe. You do have to drill holes for the fans and air-scoop retaining bolts, and cut a small bit off the bottom rail to get it to fit inside the sub-frame - but being aluminium makes that very easy.

On advice, I also drilled a small hole in the thermostat to act as a jiggle valve to aid the bleeding process....just waiting for 15L of Type D coolant to arrive now

[stephendell]

Brilliant. Does that mean we might see you on Saturday then

Hi Stephen....I'd like to but all depends how the bleeding and bumper refit goes. Oh and that pesky thing called work gets in the way as well but I'll do my best