Hi,

I need to do a complete coolant fluid change and wonder what would be the adequate DIY steps to do this?

I could find numerous youtube videos and threads on the topic and most of them are done by simply opening reservoir cap and removing the hoses on the front radiator. Then filling it up with or without vacuum kit. However, I could find videos where VCDS steps are detailed about enabling coolant bleeding before the drain and testing it after refill. Looks like the procedure could vary based on type of engine as well. So my questions:

1. For the model and make in the subject, do I need VCDS to open valves/pumps before I want to do a complete drain?

2. Is using the vacuum kit enough to not need to run VCDS bleeding tests afterwards?

3. What could happen if VCDS bleeding test is not done after the change? Could I fix it with simple workarounds while using the car until I get to someone who has this tool?

4. If I choose not to use VCDS, do I need to run the engine to reach approx. the operating 90C temperature so then stuff(pumps, valves, ??) would open automagically and I could do a complete drain?

5. I plan to replace the heater matrix(silica bag problem most probably) and I wonder what would be the best sequence to do this? Like using coolant system cleaner first and draining the coolant, replacing the heater matrix and do some rounds of flushes before filling it with G12+? Or do the flushes before the matrix replacement? Or not do flushes at all?

For reference here is my little collection on the subject:

• coolant change: https://www.youtube.com/watch?v=89qDpmOtC2U

• trick to remove air: https://www.youtube.com/watch?v=JnTUr0SEJBw 

• using VCDS to bleed the system: https://www.youtube.com/watch?v=t854UeaUvNA

Any tip is very much appreciated!

Thanks!

Hello, welcome to the forum.

Just be aware that air locks can be a serious issue unless the system is properly bled.

I chickened out and leave coolant changes to the garage for our EA211s.

When I had my heater matrix replaced they (my VAG independent) flushed it twice.

They have ODIS (I have vcds but never hooked it up after) and said the coolant bleeding function "runs on" for 150 miles to bleed more air out. I cannot remember what it does to achieve that but VCDS functions would probably be a good plan to use to help with the fill.

They vacuum filled it for certain as they are a bugger to get the air out.