My digifant manual doesn't say anything about Temp Sensor II having no
affect after engine is fully up to temp.
I have never heard of anything like that, or ever had a reason to think
that.

Is there a symptom or problemyou are working on ?

yes ....the impeller wheel on the water pump can be various types.
I never recommend the paddle wheel style ..
only the 'volcano' shaped one- plastic or metal.

on I4 engine conversion the water pump pulley diameter matters..
too large and flow is not enough. Have not had a problem with too small
a pulley and too fast flow or cavitation.

water pump impeller face needs to be decent ..they can get corroded.
Are you having some cooling system symptom that is a concern ?

Scott
On 9/24/2013 2:22 PM, neil n wrote:
> Hi all.
>
> This is for my Jetta swap, but may pertain to the WBX.
>
> The Digifant manual and archives suggest that when the engine is up to
> temp, the temp II sensor has no effect on the ECU or other components.
> But if the sensor is heated beyond 100º C, will it have any effect on
> the ECU or other component? i.e. change the engine timing? Or would it
> reach 0 Ohms and the ECU just wouldn't see it?
>
> (under Motronic, if temp II sensor or its' wiring fails, the engine
> management reverts to a preset temperature. I have no idea if an
> overheated sensor would cause this to happen)
>
> For some time now, the coolant expansion bottle has leaked a very
> small amount of coolant out of the vent. This likely happens when
> climbing long steep grades on a hot day. May be a failing or bad cap.
> Easy fix. Or, maybe the Jetta coolant pump is being pushed beyond its'
> specs. There seem to be different pump vane designs. Except for the
> long pipes, which are ok, the entire cooling system was brand new at
> time of swap.
>
> Thanks
>
> Neil.
>