Thermostat problem!!!

[Darby Vw polo]

hey guys Iv just changed my thermostat on my 6n and i noticed that the car gets up to temp fine. but when the heating is on the thermo gauge goes dwn to the first big marker on the gauge, any ideas on what is going on???

[gaz2000]

check that the new thermostat has located correctly

also check the condition of the thermo housing,there plastic,and the section holding the pin from thermo can break

[Darby Vw polo]

what position is the themo supose to be in?? is their a specific way it should be in???

[Tim_GTi]

Has the water been topped up properly? As there may be an air pocket in the system.

[Polo_SA]

I have a similar issue with my Polo. In my case I don't have a thermostat that regulates water flow so the water circulates continuously. My car takes longer to get to normal temp and as soon as I turn on my AC the temp gauge goes down to the first marker as well. Even when I get onto the highway or an open road and I drive constant speeds of 100 Km/h or faster the temp gauge also goes down to the first marker and stays there until I slow down or come to a standstill. I have had the car to 3 different mechanics and they all say that it is fine and I should not worry. When I had a thermostat in my car this was not happening, only once the thermostat was removed this started happening. My friend's car does not have a thermostat either and his car does exactly the same thing. Temp gauge drops when running AC. He has been driving it like this for years and no problems.

Is it possible that your thermostat was incorrectly installed or that it is not operating properly? Maybe it is not opening and closing properly as it should?

[sylvester]

As already mentioned the thermostat pin should locate in a hole in the housing ( possibly the part that detaches from the main housing), this is known to break and prevent the thermostat working.

[Darby Vw polo]

It's a brand new thermostat, the locating pin is located in the housing, so maybe it is the system that needs topping up. I'm gna double check tonight.

[Lowrider6n]

if the plastic pin locator breaks the car will overheat...not drop in temp, as when the pin extends when it gets to temp its got nothing to push up against to open the stat to let the water though... if you are not running with a thermostat theres no problem the water just keeps circling the system, so it will take ages to get hot, so when u drive the temp will drop because the radiator is getting hit with cold air, and when your not moving its not so the rad isnt so it'll get warm