Can anyone tell me what this is?

[bernk]

It was bolted to the side of the coolant reservoir. The lead coming out of it went nowhere and was just loose in the engine compartment… I suspect it's some sort of sensor, maybe temp, but there is a temp sensor that is screwed *into* the engine and actually connected to the temp gauge, so I'm not sure. Any ideas?

[Jammer]

Capacitor (sometimes called condensors back in the day). Probably attached to something as a strategy to reduce electrical noise once upon a time. On older boats active during the LORAN era it is common to find a concerted effort at controlling electrical noise as these systems were extraordinarily sensitive to it.


I would think that you can safely just bin it.

[catalystcat]

Yep. A couple of examples -- https://www.ebay.com/itm/164719774497

https://www.newera.co.jp/en/product/...or_condensers/

(In addition to noise suppression, they were also common in old distributors, near the points.)