Gauge in Oil Pan

Thanks Curt,

This makes sense to me now. The rubber cover must have been installed because the float wasn't there.

I guess the oil level light is another thing I can live without for the time being.

Hi Richard :
There is supposed to be a wire (like welding rod) and a float attached to the inside of the sending unit. These things work like a gas gage in most 40-50's cars. You have, in the bottom center of your speedometer a circle about the size of a dime. This will light up red if you are low on oil.
There is supposed to be a red wire that attaches to the sender. It works on completing a ground like a door courtesy light switch.
Cheers
Curt

I just finished cleaning out the crud (it was pretty clean, actually) in the oil pan of my '34 8-cyl.

I noticed in the side of the pan, a gauge about 2" in diameter stamped "Stewart-Warner". It has a raised triangular part on the cover and a single, threaded wire connection and nut (which isn't connected to anything on my car). Inside the pan, there is a convex rubber cover and no visible probe into the oil sump.

What is this thing and what is it supposed to be connected to? Is this the sensor for the oil level light (I thought that operated off the floating oil pick-up screen), or is it for something that is not on my 850Y, like an oil temp gauge? I don't see how anything can read through that thick, rubber cover.