Can anyone suggest what might be happening.

I had a problem about three months ago where, very occasionally, the temperature gauge would suddenly shoot up and then settle down if I slowed to 45/50 mph, opened the windows and turned the heater fan on full. I took it to my service dealer who concluded I needed a new water pump and charged me accordingly. The same thing has happened again - strangely though (and I don't know if there is a connection), the car struggled to start first thing in the morning - something it normally has no problem with, then drove normally for 200 miles down the motorway before suddenly exhibiting the same problem with the temperature gauge. I stopped at services, removed filler cap and syphoned out some coolant - (which was hot, as I'd expect after 200 miles at a steady 70 - but I couldn't say was unusually hot as i've never had to check it mid journey before) - I replaced about a pint of existing coolant with some cold water and went off again. Same thing happened within a few minutes. This time i limped to the next services doing about 40 and annoying all the trucks. Here I stopped for 35 minutes - did the same syphoning/replacing of about a pint of coolant and went off again. Car was absolutely fine for remaining 70 miles of motorway driving.

I'm wondering whether i ever had a problem with the pump at all, whether there might be another explanation and whether the temperature gauge reading might be false. I'm not brave (or foolhardy) enough to ignore the gauge and drive on. I know I'll have to go back to the garage but I first wanted to check if anyone else had similar experience/symptoms.

Im a complete noob to skoda and VAG, but what I gather is that there has been lots of problems with coolant temperature sensors, it is certainly very strange what you say, for the temperature to suddenly shoot up, providing there is coolant and pressure it shouldn't really change that much to be honest. have you have it scanned on the diagnostics? Might throw up a couple of fault codes or something?

If its the 8 valve MPi engine, it's extremely likely that the thermostat has broken up and is contacting the temperature sensor, causing it to give out an implausible signal. A new complete thermostat housing with temperature sensor is around £45ish, part number 047121111S (I think). They can check it by removing the engine cover and the sensor and having a look/feel in the thermostat housing.

Buy the modified thermostat from Jorily, designed not to break up.

Ooh sounds good anewman. Not the first time you've been most helpful. Thanks.

If its the 8 valve MPi engine, it's extremely likely that the thermostat has broken up and is contacting the temperature sensor, causing it to give out an implausible signal. A new complete thermostat housing with temperature sensor is around £45ish, part number 047121111S (I think). They can check it by removing the engine cover and the sensor and having a look/feel in the thermostat housing.

Thanks for the feedback. Actually, it's a 16v 1.4 petrol fabia estate.

A mate of mine just suggested there might be an airlock in the cooling system - could this account for such symptoms?

Thanks for the feedback. Actually, it's a 16v 1.4 petrol fabia estate.

A mate of mine just suggested there might be an airlock in the cooling system - could this account for such symptoms?

It happened again last weekend when I started the engine after the car had been stationary for 4 hours, so I knew it was cold. I had a sizeable motorway journey ahead of me so, even though I was 99.99% sure the temperature gauge was showing a false maximum, I called the RAC out. After hooking up his notebook to the car's computer he told me I needed a new temperature sensor. Took it to my Skoda dealership and all seems to be working fine now - even the aircon seems to be working properly now.

Thanks for the tips.