Coolant change

[gravis]

So after only 1 week of ownership I've gone and mixed the coolant, added silicate to oat. I'm guessing j need to completely flush the system, is there a how to on here anywhere? Thanks


Sent from my iPhone using Tapatalk

 

[Felix.]

Take the bottom hose off the radiator and allow to drain. Fill the car back up with clean water and drive the car about a bit. Allow to cool (few hours) and drain again. Do this a few times, then it should be thoroughly flushed.

There will be a more complex way of taking off a number of hoses and back flushing, but i find the method above a lot easier.

After its flushed enough, then replace with new coolant.

 

[gravis]

Thanks for this, I did as you said and also disconnect the aux heater and back flushed with a hose in both directions. Also back flushed rad and rad pipes. Problem now is that I'm only getting around 4.5 litres of coolant back into the system. It's been like this for a couple of weeks now and we've done a few long trips and the level is not going down. Temp sensor seems normal and getting hot air through the blowers however idle is a little rough, it keeps hunting a little when starting from cold. Any ideas? Could it all be related to air in the system?


Sent from my iPhone using Tapatalk

 

[gravis]

I took a video of what's happening to the car, it can be seen below, sorry about the darkness but hopefully audio will be enough for someone to advise... It's running rough at idle and also has a slight hooting sound...

youtu.be/Z4TVNsfXVGU

I've also got the following fault codes via vagcom:

5 Faults Found:
17965 - Charge Pressure Control
P1557 - 35-10 - Positive Deviation - Intermittent
17664 - Engine Coolant Temp Sensor (G62)
P1256 - 35-10 - Open or Short to Plus - Intermittent
17978 - Engine Start Blocked by Immobilizer
P1570 - 35-10 - - Intermittent
18080 - Coolant Fan Control 1
P1672 - 35-00 - Open or Short to Ground
17552 - Mass Air Flow Sensor (G70)
P1144 - 35-00 - Open or Short to Ground
Readiness: 0 0 X X X

Any help greatly received!


Sent from my iPhone using Tapatalk

 

[Felix.]

4.5 litres will be about right - you'll never get all of the old water out of the car. Make sure you have enough anti-freeze in the system though. Simple way is to take a sample out of the expansion bottle and put it in the freezer over night. If it freezes, then you will need to drain some coolant out and put some more neat anti-freeze in.

The fact that the level is not going down is a good thing - it means you have no leaks

The 'hunting' could be a whole host of things to be honest. Have you tried disconnection the MAF sensor and see if it makes a difference?

 

[gravis]

Oh ok I was under the impression that these cars take between 8-10 litres? I'll try the freezer test as you suggest.

I've not tried much regarding the 'hunting' to be honest. I will try the MAF sensor though. It just seemed strange to me that it started after I changed the coolant but I suppose it's possible some water got into one of the sensors wiring as I did spill a bit of water over the engine when I was back flushing :/


Sent from my iPhone using Tapatalk