Hey guys, I'm having some problems with my ED6 Hatchback. I noticed the other day when I was driving long distances that it would start to overheat and then suddenly the needle would drop as if it was instantly cooled. Some smoke started coming out of the motor and I'm confused like none other. Checked the hoses and they were all fine, the radiator is fine and it has enough antifreeze. Any suggestions?

 

Thermostat? Maybe it was seized and then suddenly got unseized? though i've never heard of that happening...
If the needle suddenly dropped i'd check the Temperatur sensor. I think it should be near the upper radiator hose with one wire coming out of it.