Morning people.

 

I've just acquired a 9n Polo 53-reg with BBY 1.4/16v engine, 117K. 

It runs low (80-ish°C) on the temp gauge, and that hasn't improved much with replacing the CTS with a known good one.

Presumably a tired thermostat then?

When I look here I see a choice of two, rated at different temp ranges 87-102 Henschel or 83-98 Himmermann. That's looking up for a 2005 Fabia, 2003 Polo gives same info.  Anyone know why there's two different ones? The one fitted seems to have a cover part number corresponding to the Himmermann version, but I guess the main question is - would you expect to see a lower temperature on the gauge, corresponding to the 83°C start-of-opening temperature?

 

I'm thinking no, that the gauges are probably calibrated to read 90 whatever?

 

You'd be right, the needle should sit dead centre, these 'stats have a propensity for sticking partly open.

 

It is the ECU which supplies the signal to the gauge not the ECT sensor, the needle will sit dead central within a range of temperatures that the ECU considers to be normal.

 

The difference between the two 'stats listed may be because one is specced for cold climate operation, the engine cooling fans are perfectly capable of keeping the engine cool irrespective of climate but there is no controllable way of warming a car up quicker other than by keeping the 'stat closed for longer.

Nice one, thanks. 

Didn't realise you could still get winter or summer stats these days

New stat fitted. Solid 90 reading now.