I pulled the GM dash mount compass out of storage and found the liquid inside leaked out. I found the leak, but what is the liquid? It has a smell of oil but not sure. It's clear so I know it can't be water due to freezing. Any idea of what to fill it with so the compass doesn't bounce around? :confused:

A light mineral oil would be my guess.

Yep, oderless mineral spirits...
That's what boat compasses use.

They were filled with mineral oil. The viscosity allows for free movement without letting the needle bounce around.

factory gm compass for 1967 thru 1969 dont have liquid inside them. PN 1#986298 I looking at it right now N.O.S You could have a earlier or later year one? Iam sure someone else will confirm this.

The model # is 983335 if that helps.

Where exactly does it get mounted?

Gary, The instructions I have for compass 986298, shows to mount it in front of the dash on the btm of the windshield, behind the radio speaker grill.
It attaches to the windshield with a suction cup that comes with the compass. I had one in my camaro for several years, but took it out because in a conv it could easyly be stolen. The suction cup is made from rubber that rots from age even in my NOS box. I replace it with a round plate about the size of a half dollar. Then i glued it to the winshield with rear view mirror glue. graemlins/waving.gif

Thanks for the info. I'll glur mine as well. graemlins/thumbsup.gif