Strange temperature readings

[cliovicky]

My temperature gague in my 172 is weird sometimes its ok and most of the time is jumps around never goes over half way ( which is where it normally sits). But it flickers, very odd. Anyone else had this problem?

 

[Fletcher]

Mine seems to fluctuate between the centre, and line below.

 

[Mark One]

if it's actually jumping around and not moving slowly it's one of two things.

1) you have a bad electrical connection (probably at the sensor would be my guess)
2) You have quite a large amount of air in your coolant system (the gauge reads very low when the air passes) - this is very bad. You'd need to make sure the system is properly bled.

 

[cliovicky]

if it's actually jumping around and not moving slowly it's one of two things.

1) you have a bad electrical connection (probably at the sensor would be my guess)
2) You have quite a large amount of air in your coolant system (the gauge reads very low when the air passes) - this is very bad. You'd need to make sure the system is properly bled.

Well it 'floats' if that makes sense. It only does it now and again, been fine since i posted this. Why would air get in the coolant system ? it aint been touched and it only does it every now and again. I thought it was just a connection problem.