With over heating I meant that maybe sth inside of the alternator is damaged - bearing, voltage regulator ?
what's the difference in resistance when driving around the city instead of highway ?
I will check your suggestion but beside that I'm looking for logical explain or maybe car electrical...
Your comments are highly appreciated.
This courious me also that if alternator or battery would be the case then other gauges should be affected - I need to mention that the light of the fuel reserve sometimes works, other time not - not sure if it's is correlated ?
What is also interesting...
regarding conty do you mean between gauge on the desk inside and the sensor in cylinder head ?
thermostat is working fine - it's easy to check and I did it.
I think it's not related to the grounding because it should be visible every time I run the car and it's not.
My thought it's related to...
As I mentioned I already checked cooling system - if it would be cooling system why it did not happen during city crusing ? why gauge is going up and down when turning on/off lights ?
there is something wrong with electrical system but I don't want to change half of the components so I'm looking...
I'm pretty sure that it's not a problem with cooling because it's not possible to cool down temperature in so short time. Additionally there is a moment on the video when the driver is turning on and off the lights and in this time the gauge is also moving up and down.
I'm not sure if there was already such a problem decribed on the forum - if yes please share a link if not maybe somebody could help.
There are few people with a same problem and one of them put a video on YT to describe better a problem.
It looks like a electrical problem...
"Condition: In perfect working order with no crunches or whines at all was purchased from a reputable Honda breaker on here just over a year ago only selling as I have since sold my car and have no use for it any longer" - so the condition wasn't checked by you ?