Having read the horror stories about the cooling system on my S3 I decided to change the coolant expansion bottle 'With silicone' for an O.E. coolant expansion bottle 'without Silicone' as looking through the cap hole I was not able to see the 'Bag'.
This turned out to be literally a 10 minute job
Firstly the two pipes were unclipped off the side of the expansion bottle and the electrical connector for the level sensor was disconnected, the 2 plastic securing clips at the back of the bottle were then released with a flat bladed screw driver, which meant that the bottle could be raised enough to get a jug underneath it.
Then using a pair of pliers releasing the small diameter expansion hose from the top of the bottle, the bottle can be tipped into the jug and emptied. (Fluid will not come out of the cap hole very well) the larger hose on the bottom of the bottle can then be released again with pliers and the bottle removed.
My bottle had a build up of scum inside it at just above the maximum level but no evidence of a 'bag' inside it.
it was then just a simple job of replacing the pipes and clips onto the new bottle and refilling it with freshly mixed G13 fluid, and then placing it down onto the plastic clips, I did this thinking that the higher it was during filling the less likely that air would be trapped in the pipework.
Parts used:-
So this job has raised a mystery,,, where is the silicone bag ??? did the previous owner remove it? I doubt the previous owner even had the bonnet open!! If the bag bursts does it then decompose and totally dilute into the coolant? currently my heater operates as expected, although I have had one incidence of the fluid level changing I am not regularly using fluid and there were no signs of fluid on the undertray when I removed it for servicing! I suppose the answer to all these questions is 42.
This turned out to be literally a 10 minute job
Firstly the two pipes were unclipped off the side of the expansion bottle and the electrical connector for the level sensor was disconnected, the 2 plastic securing clips at the back of the bottle were then released with a flat bladed screw driver, which meant that the bottle could be raised enough to get a jug underneath it.
Then using a pair of pliers releasing the small diameter expansion hose from the top of the bottle, the bottle can be tipped into the jug and emptied. (Fluid will not come out of the cap hole very well) the larger hose on the bottom of the bottle can then be released again with pliers and the bottle removed.
My bottle had a build up of scum inside it at just above the maximum level but no evidence of a 'bag' inside it.
it was then just a simple job of replacing the pipes and clips onto the new bottle and refilling it with freshly mixed G13 fluid, and then placing it down onto the plastic clips, I did this thinking that the higher it was during filling the less likely that air would be trapped in the pipework.
Parts used:-
So this job has raised a mystery,,, where is the silicone bag ??? did the previous owner remove it? I doubt the previous owner even had the bonnet open!! If the bag bursts does it then decompose and totally dilute into the coolant? currently my heater operates as expected, although I have had one incidence of the fluid level changing I am not regularly using fluid and there were no signs of fluid on the undertray when I removed it for servicing! I suppose the answer to all these questions is 42.
Last edited:
