A bubble in my Compass

I don't think I've had a liquid filled compass without a bubble. It gets bigger and smaller with temperature.

More expensive compasses will have some mechanical device to take care of liquid expansion. I've never bought one that expensive.

https://www.youtube.com/watch?v=eB7FYwhcM4Y

watch this video and fix yours.

Here is a video showing that a bubble does affect function of the compass.

Bubble in Compass from Google Search

Bubble has no effect on compass operation,Ignore it.

I've heard switching to Penzoil will help :)

I would bet leaving it on the dash is the culprit, as it gets super hot on the dash. The oil expanded and then probably leaked a little & after cooling back down air bubble. Time to visit Wallyworld for another. :(

My hand held compass has a rubber button for filling. I can also use a hypodermic for sucking out the air. See if yours has a rubber button around the perimeter.

I have a surveying compass/inclinometer that I no longer use because of the smart phone app SAToolz that lets you see where the sats are located and if anything is blocking the view.
I would not worry about a air bubble... just keep it off the dash.

I have had the same thing happen to an expensive marine compass. They are oil filler with a diaphram to allow for expansion as temperature changes. To fix it I had to send it to a repair shop. A new one would have cost more than the repair. The boat compass is out in the sun all the time.

That part about "left it on the dash..." is the likely cause of heating it. ST