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Removing silica bag from coolant header tank
- Thread starter BigJimNoFool
- Start date
Well, a slight flaw in that logic, not all engines have cambelts and not all engines that have cambelts have a "service replacement period" on the cambelt, ie EA211 engine cambelts only need replaced as and when they show signs of wear and tear - and the coolant system does not need opening up on some engines when the cambelt is replaced.
So, I'd consider that as G12evo is described as a "for life" coolant and so I hope that no cars that leave the factory filled with it have/need silicate dosing system, and so that means that frequent coolant changes will not then be necessary. If that is true, and can anyone that has a recent(ish) car factory filled with G12evo confirm that their car does not have any form of silicate dosing system - or "mit silikat" on the coolant reservoir, then after replacing the G13 maybe 5 years after removing the silicate pouch, with G12evo, no further change of coolant should be necessary.
Good startAsked the mechanic that’s fixing my car at the moment through insurance about this. They said they’d never heard of the silica bag before…
Agreed and accepted, though I was under the impression that the silica bags were only in the diesel engines, and all the VAG diesel engines were belt driven. My 1.6TDI Leon had the silica bag in, and I removed it, but my 1.2TSI Toledo is chain driven and does not have the bag
The "only fitted with diesel engines" is what I initially thought as it was said that it was the higher temperatures at times that caused the need to bolster the silicate in the coolant, but it turns out that that might have been true at one time, but not later on. My older daughter's late 2019 Leon Cupra certainly was fitted with one of these coolant reservoirs at the factory.
in service manual for EA888 (1.8tsi, 2.0tsi) and also for diesel EA288 there is mandatory to use vacuum filling - pump and refill/ But is it possible to do without this tools (compressor, vacuum set etc)? I removed hose from radiator (in fact i pull out coolat temperature sensor at radiator outlet, because hose stucks) and I was able to flush only 3.5litres of 10l in total. So is any trick how to pump out main part of coolant?
Next problem is to bleed system, despite fact that highest point in system is return hose to coolant reservoir - it should be selfbleeding. But selfbleeding takes time and needs opened valves and all lines in system, which is achieved when temperature of engine is at operating range -> but until it achieves it, air capsules/pockets can cause local overheat and damage.... I discover in diagnostics VCDS in Adaptation some entry related to valves, and also in Basic Setting which should open the valves also below operating temperature (allow to purge air pockets before engine heats up) https://forums.ross-tech.com/index.php?threads/25738/ ... so does anybode say more to this or how to replace as much as possible coolant without risk at home ?
Next problem is to bleed system, despite fact that highest point in system is return hose to coolant reservoir - it should be selfbleeding. But selfbleeding takes time and needs opened valves and all lines in system, which is achieved when temperature of engine is at operating range -> but until it achieves it, air capsules/pockets can cause local overheat and damage.... I discover in diagnostics VCDS in Adaptation some entry related to valves, and also in Basic Setting which should open the valves also below operating temperature (allow to purge air pockets before engine heats up) https://forums.ross-tech.com/index.php?threads/25738/ ... so does anybode say more to this or how to replace as much as possible coolant without risk at home ?
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I only ever now use a coolant vacuum refill kit for these reasons, along with VCDS where it is needed.
Update: the mechanic has ordered a new coolant tank which comes without the bag. My current tank does have the silica bag, which is still in tact (surprisingly after almost 100k miles…). They’re still gonna swap the current one over to the new one to avoid the heater matrix issue.
Thanks for highlighting this problem @BigJimNoFool. Just took mine out to save me from any future pain!
The only thing I can suggest is to remove as much coolant as possible. Due to having an overheat issue, I had my waterpump changed, so asked my mechanic to remove as much coolant as possible. They took the bottom rad hose off, so along with the pump change AND a new thermostat housing, there wasn't a lot of the original coolant left.
It all got put back toghether and new coolant added. I then changed the matrix. I drove the car, let it cool down and topped up about 4 times over a few days. After that, it was fine. I may have been lucky but I've had no issues.
It is certainly not as thorough or technical as the VAG process, but nearly 3 years later it is still working fine.
My mechanic noted that a lot of debris (casting sand) seemed to get trapped in and around the thermostat housing area. It seemed to be a natural riffle, that traps the debris like when paninng for gold. Except it's not gold.
Mine is out. I also saw my papers. Before 2 years i had a thermostat change under guarantee and they filled it up with G12evo coolant.
The TDI EA288 184 cooling system is rather 'complicated' with 3x coolant pumps, (1x electro/mechanical & 2xelectro) 4 circuits, and many one way valves.
As you have found just dropping the lower rad hose like in older cars won't remove much of the total volume of coolant.
Flushing the cooling system it is described in the workshop manuals saved on here. You need to basically block off 3x circuits and flush the remaining open one, and do this whole procedure twice.
I made my own vacuum filling device using my air compressor as a vacuum generator and a few valves. Worked great. You can buy "Cooling System Vacuum Kits" for not much money which would be easier and what I would do if/when I do it again.
Don't flush the system with your new heater matrix as you may flush the detritus through your lovely new matrix blocking it up! Flush need to be done with the OLD matrix in place!
There is a diagnostic procedure following a coolant system flush/re-fil to help bleed any remaining air but I doubt many actually do this!
Yes if the silicate is just in a soft pouch or the original mesh tubes, not so I'd think that if it is in the later double skinned reservoir, that will be a different story.
Double skinned yes, but surely that second skin isn't sealed, and the silica bag is still open to the rest of the system. The bags can't go in before they plastic weld the reservoir together, sealing it in position, surely??? I was lucky, I could get mine out with my fingers
As these silica bags serve an important purpose, is it not possible to just periodically replace it with a new one? That's if they're available to buy. I'm assuming they split due to age from going through 1000's of heat cycles which deteriorates the plastic.
This is the 'double skinned' version I had in my 2015 184TDI - no removable 'Tea Bag'
You cannot remove this type of silicate repository without destroying the tank.
I have my doubts whether this type can actually leak? and if it did the coolant return flow would have to be strong/fast enough to carry the granules up and over the container which again I doubt as there isn't much flow through the coolant header tank return pipe.
I changed mine anyway to a tank without Mit'Silicate. 'just in case!'
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