thermostat

I have a couple of seals leaking in my thermostat housing ( fsi )
Ordered, but I have also snapped off one sensor and Im not sure what its function is?
Its not the green one ( dual temp sender ) It is the one sitting inside thermostat cover
Have attached picture of it


This sensor is hold in place by a metal clip. Its two stems seems to have been soldered to the base so when pulled away it just snapped

wpaul said:

I have a couple of seals leaking in my thermostat housing ( fsi )
Ordered, but I have also snapped off one sensor and Im not sure what its function is?
Its not the green one ( dual temp sender ) It is the one sitting inside thermostat cover
Have attached picture of it
View attachment 8979

This sensor is hold in place by a metal clip. Its two stems seems to have been soldered to the base so when pulled away it just snapped

Click to expand...

The FSI's have what's called a map controlled thermostat. What this means is that the thermostat has a heating element attached to it so that the engine can send a signal to heat up the thermostat and in turn control the flow of coolant around the engine. The purpose of this is to be able to better control the flow of coolant, different 'maps' are stored for different engine conditions - under load etc and I also believe it even takes into account the speed of the car as another parameter. The whole idea behind this is that there should be an increase in efficiency of the engine as the thermostat doesn't solely rely on the temperature of the engine/coolant to control flow. I think what you point to maybe the heating elements for the thermostat?

Cheers Rob.

The whole cover with thermostat is called pipe union with heater element so yes it is a heater element.
Thank you for very extensive and clear explanation.
I wonder how my economy will be affected with this thing broken.

Im running my car without this sensor. Mechanic tried to solder it but it didnt work.
Car has engine managment light on and also heating/air conditioning is affected ( unless its switched off it will make radiator fan work constantly )

So far I dont know the effect on cars fuel economy but I could drive the way it is now if not heating/air con problems.
Car seems to warm up so much quicker ! Under 2 min I suppose. It used to take much much longer.
Im gonna fill up today and see what its like fuel-wise

Edit
Miscalculation in regards to engine warming up time. Its the same.

wpaul said:

Im running my car without this sensor. Mechanic tried to solder it but it didnt work.
Car has engine managment light on and also heating/air conditioning is affected ( unless its switched off it will make radiator fan work constantly )

So far I dont know the effect on cars fuel economy but I could drive the way it is now if not heating/air con problems.
Car seems to warm up so much quicker ! Under 2 min I suppose. It used to take much much longer.
Im gonna fill up today and see what its like fuel-wise

Click to expand...

This is interesting! It's surprising what an impact it has on the speed of warm up. Keep us informed on the effect on fuel economy.

Cheers Rob.