We've pretty much given up on attempts to repair the stock coolant temp gauge & sensor system. �Have swapped out the instrument cluster, replaced the sensor and walked the wire. Still pegging max high with a steady flashing light, but the thermal laser gun reveals a normal temp system.
There was a posting recently on "slime" affecting the level sensor in the pressure tank, and I plan to share that with the tech. �I suppose that would only affect the blincking light anyway, not the temperature reading.�

The tech working on it has found a completely independent (of the stock system) aftermarket coolant temp gauge and sensor and he plans to install that over the next two days.
One thing is unanswered in my mind. �Does the stock sensor give temperature readings to the ECU? �I'm wondering if this is one of the reasons why my fuel economy has dropped from 18-19 to 16-17, i.e. running rich. �Furthermore, if the ECU does get data from the stock system, how will the aftermarket system get tied into the ECU? �
I haven't talked to the tech about this yet and wanted to get the ideas of the list.
Thanks, Anthony'89 Syncro GL 2.1 (Hidalgo)�