All. At idle I had a little jump in revs. It was minor and someone suggested temp sensor. So for a fiver I thought id change it.

Now before on the old sensor it used to warm up to 90c and go no further.

The new sensor seems to take an age to warm up. It will ONLY hit 90c when stuck in traffic. Anyother time its between 50 and 60. Which seems really low.

This was after 1hr driving to north wales on motorway and country lanes (and not going slow either).

most likely the thermostat stuck open, had this last year on mine, if u replaced the temp sensor did u buy a proper one? and not a cheap replacement?

£5 seems to cheap for a sensor martin lol

Looks like thermostat mate, same symtoms mine had. But buy a genuine temp sender.

Was the temp gauge ok with the old sender ?

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£5 sensor

I had the exact same probs a few weeks back. I changed the thermostat and an OEM coolant temp sensor (part no. - 059919501A) and the idle improved and the temp gauge read 90c after five-mins driving.

 

Here's the guide i used to change the thermostat for a mk1 1.6 http://uk-mkivs.net/topic/62135-coolant-thermostat-change/