Technical overcooling

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Technical overcooling


New member
Oct 22, 2011
i have fitted a new thermostat and temperature sensor but stll think the the enginge is over cooling because i know when the thermastat is open because the temp guage drops however the temperature guage does not rise to the middle mark until i make the enging work on a incline but drop again as if undercooling is the engine runing efficiantly or is there a problem.
Sounds fine to me! My W reg Mk2 never goes above half way on temperature gauge. If the radiator and fans are doing their job properly, then happy days. Don't fix that, that ain't broke.
what car? age model engine? my 1.3 multijet goes up and down a bit in cold weather but its probably not the same in a 1.2 petrol.

as a general rule it should sit in the middle of the gauge but thats probably more down to the thermostat than the sender unit.
in the winter my mk2 1.2 8v would easily loose engine temperature when i had the interior fan on

After winter it didnt improve and god worse, having to labour the engine for long periods to get it up again, only to loose quickly again = dodgey thermostat
The seal wasn't old, but had failed and was letting too much past = Rapid cooling

If the car takes forever to warm up - suspect stuck open = replace
Warms up and quickly cools - suspect seal damage = replace
Engine overheats - Stat stuck closed = Replace

Ive changed the stat in mine after a seal failing, new one worked perfect, guage was sitting in middle of dial, but recently its only getting to 71c, then dropping back down, rising again to 71c, then eventually settles there.

Took it out to test it, and its opening too quickly, stated opening temp is 87c.

Probably will replace it when ever I get round to it, provided the motor factors will take it back as faulty..