If your car is saying the coolant level is low and it clearly isnt it could be because of this. Its a common fault and ive changed loads of them. The sensors rods cake up so cant sense the fluid level by completing a circuit through the coolant. The revised sensor in the expansion tank has a different design as seen in the photos. Also you will see the part number has changed to reflect the upgrade. Hope this helps anyone doing a search and a very easy fix. Main dealer expansion tanks are relatively cheap as well.

Hi Fireman, is the upgraded tank 'Mit Silicat' or without?

With...and thats why its important to use the right grade antifreeze 

On 12/10/2020 at 18:40, fireman said:

If your car is saying the coolant level is low and it clearly isnt it could be because of this. Its a common fault and ive changed loads of them. The sensors rods cake up so cant sense the fluid level by completing a circuit through the coolant. The revised sensor in the expansion tank has a different design as seen in the photos. Also you will see the part number has changed to reflect the upgrade. Hope this helps anyone doing a search and a very easy fix. Main dealer expansion tanks are relatively cheap as well.

I do not like the colour of that 407 A tank.  That looks like the Silicat has split.  @fireman now that you have changed your header tank, this is good news.  How is your heater matrix doing?  Check the heating (turn it up to maximum) and see what happens.  You might want to consider a coolant system flush.

On 12/10/2020 at 18:40, fireman said:

 

 

With that prompt from Fireman I've ordered a new, upgraded expansion tank which I will fit when it arrives. Will also change coolant if possible (G13) 

I've just had a new 'M' revision tank fitted by a main dealer and it was without the silicon bag.....in fact, it doesn't even have G12 or G13 on it!

7 minutes ago, MeteorOcty said:

I've just had a new 'M' revision tank fitted by a main dealer and it was without the silicon bag.....in fact, it doesn't even have G12 or G13 on it!

I hope the stealer has fitted OEM, not some cheap copy.

9 minutes ago, MeteorOcty said:

I've just had a new 'M' revision tank fitted by a main dealer and it was without the silicon bag.....in fact, it doesn't even have G12 or G13 on it!

Yes G13 is out,G12 evo is “new” one and without silica bag

1 hour ago, Warrior193 said:

I hope the stealer has fitted OEM, not some cheap copy.

Yep, defo genuine! Dad has a 2017 Octavia since new and his is the same.