Kymco Dink LC 50 thermostat going crazy

Hey guys,

My daughter asked me yesterday if I know why the thermostat keeps going into the red. Topped up the coolant since it was down a bit and took the scoot for a quick spin. After about 1/2 mile, the needle suddenly shot like a rocket all the way to the top. I decided best head for home and have a think, so I turned around and, coming back down the hill, opened the throttle wide. This time the needle plummeted equally as quickly as it had shot up earlier. I decided to drive around a while after all, and found this "up/down pattern" repeating itself at random. Any ideas what's going on here?

Thanks in advance

 

Is coolant leaking around the thermostat housing or under the scoot? Have you checked the gauge itself?

 

Thanks for the reply, Milo. There's no coolant leaking - I had just topped it up because it was a bit below the max line. Might sound a bit dumb, but could you please explain what you mean by "check the gauge itself"? Not sure I know how to do that

 

I mean the temperature gauge if you have one. Could be faulty diode but probably not. I can't think why the needle is fluctuating so rapidly :/