low temp thermostat

[Martin]

Just thinking out loud here but if I run the slightly cooler thermostat (so that I know its open a tad longer when the car is parked up), finding a way to force the electric water pump manually might have merits. Surely I could log that output against water temp to get an idea of when its switching and then stick in a manual override or double its on time with a timing cct or something. argh I'm running out of places to hide switches!

Hmmm

Personally I would not change the thermostat
Millions of cars world wide are turned off every day with the water temperature at 90 degrees - it's not a problem
If your engine water temperature really is over 90 degrees then the thermostat will remain open and you may well be able assist the cooling process

Logging the current operation of the electric water pump and water temperature may not give you a correlation
This is because modern cars often have interesting control logic using multiple inputs

Will the electric water pump actually help?
Depends if it's part of the main cooling system or just used to cool the turbo down
(I don't know which model Polo you have, if it's turbo or not, and my Polo knowledge is very limited)

It should be easy to wire a switch into a relay that turns both the fan and the electric water pump on - no problem there
If there is no turbo then I would certainly proceed with this approach - easy job (once you find a place for the switch - LOL)
(I guess even if it is a turbo this would be kind to the turbo temperature)