Thermostat failure?

[Adjustingdrift]

Hi guys, I recently had a fault with my car ( 2014 leon cupra 280) which was a P261800 coolant bypass fault which decided to disappear one day but as I was driving to work I’ve noticed the EML light has came on and the coolant temp isn’t moving I’m guessing the thermostats gone? I’ve attached the codes

 

[TripleBob]

Have you checked to see if the silica bag is still in the coolant expansion tank? They’re notorious for splitting and dumping all their silicone into the coolant system - blocking it up

 

[Adjustingdrift]

Have you checked to see if the silica bag is still in the coolant expansion tank? They’re notorious for splitting and dumping all their silicone into the coolant system - blocking it up

I’ve just taken a look at it and I don’t see one in there is there any other signs that it’s released it all into the coolant system?

 

[TripleBob]

If you’ve not removed it, and the bag isn’t very obviously in the tank, it’s disintegrated and been sucked into the coolant system

 

[SuperV8]

If you’ve not removed it, and the bag isn’t very obviously in the tank, it’s disintegrated and been sucked into the coolant system

Not all tank's have the 'tea bag' type silicate pouch which some people remove - If the tank says 'mit silicate' and you can't see any bag, then it will be an internal repository.
The internal type and not removable so you would need to buy a new tank if you don't want silicate - though I'm not sure these internal types can leak like the teabag types!

 

[Adjustingdrift]

Not all tank's have the 'tea bag' type silicate pouch which some people remove - If the tank says 'mit silicate' and you can't see any bag, then it will be an internal repository.
The internal type and not removable so you would need to buy a new tank if you don't want silicate - though I'm not sure these internal types can leak like the teabag types!

Mine does say ‘mit silcate” and come to think of it I’ve never seen a bag in the tank even when I brought the car i don’t think it was in there if I remember

 

[TripleBob]

Not all tank's have the 'tea bag' type silicate pouch which some people remove - If the tank says 'mit silicate' and you can't see any bag, then it will be an internal repository.
The internal type and not removable so you would need to buy a new tank if you don't want silicate - though I'm not sure these internal types can leak like the teabag types!

True, but afaik all the 280 spec Cupras had the variant of tank with a bag in it

 

[nd-photo.nl]

Correct, might also be the previous owner removed it without mentioning it.

What happens with the coolant temps? Are they too high and it spits out coolant? Or the temp stays too low with a thermostat stuck in open position?

I created a video for removing the silica bag.