Temp guage goes in the red

Hello all

My micras temp guage goes in the red within 5 mins of starting up. The lad i got it off said the temp sensor or the therostat is knackered or could he be pulling my leg? What else could it be? I dont think itll be the head gasket as there is no 'yellow gunk' under the oil cap at all?
Any ideas?
 

r-reg-sr

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Site Supporter
their is a one wire senso under where the spark leads plug in the side
unplug it to see if the needle drops
 
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