UK-POLOS.NET - THE VW Polo Forum

Hi all, hope you are having a merry xmas.

Recently I have been having an issue with my cars coolant temperature. When driving the temp gauge will hit 90, as it should, then stay at 90 for approx 5 mins. After this it will increase and increase until I turn the heater on.

I first if all tried using my friends high tech computer which controlled the water pumps and tried to bleed it. This didn't help.

Next I put a new radiator on it and this has slightly helped, in the sense that the temps don't go as high as they did, but the coolant still overheats.

I am unsure of weather there is still air in the system, or weather the thermostat is dodgey.

After long ish drives the top pipe on the radiator is stone cold, can anyone shed some light on this issue?

Thanks in advance.

Watch this, very informative. https://m.youtube.com/watch?v=4ukTilxezVw

So turns out the 1.4TDI (and other engines) has 3 inter-dependant cooling systems, but the culprit is the waterpump on the toothed belt which is controlled by a solenoid. Sometimes the metal sheath that surrounds the impeller doesn't move in effect not allowing any circulating coolant.

If you've changed the thermostat that would be the next logical place to look. Also a note about Silica bag in coolant expansion tank. Get shot of them too.

Apparently there's a VAG note about waterpump that's been issued.

Thankyou this is really helpful. Sounds like a water pump issue.

Thankyou this is really helpful. Sounds like a water pump issue.