My temperature gauge has started having a fit, drove down the road a mile or so giving it a bit of stick and the temp gauge was virtually off the scale, 2 mins later back to the middle then back to the top third then high then back to the normal...what ? any ideas? The termperature was about the only thing on the car that would stay in the same place track or road use...

 

Check all connections, failing that it will be the sender unit. Test it with with resistance meter(should be on top rad pipe) if faulty go for Defi, expensive but 100% reliable

 

Sounds like water pump failure, if you drive moderately and steady it will usually fall and climb on you stopping or accelerating. Take the header tank cap off when the car is cold and star it, if you give it a bit of revs you should see the water moving inside the tank if the water pump is ok.

 

Thanks.

I dont know if it is connected but over the last few weeks I have noticed that sometimes on starting the engine or stopping it it makes a knocking sound.

I wonder if that is also a symptom of water pump failure ?