Unidentified object in cooling hose

[Tabwela]

Wise members of the technical forum, I stand before you befuddled by a glitch in our cooling system. I changed the coolant fairly recently, and soon after that Noticed a slow leak emptying our top up coolant reservoir even when the engine is not running, causing me to top it up at every use - Drips coming off both plates that protect the hydraulic tappits, either side of the engine but no obvious source. Causes me to think it was dribbling to both sides from somewhere higher up the engine. There was some build up of dried white deposit where the short hose attaching to the expansion tank goes into the top of the water pump housing, so I drained the system and took that off. Obviously been leaking there -plenty build up of deposits on the flange, but what is confusing me most is that there was something inside the pipe! Appears to be a metal pin Surrounded by three chocks of metal and some general grime. Was this some sort of one way valve or pressure limiter? After removing it, filling the system and bringing up to temperature, the top up tank seems now to be being filled up by the expansion tank, which is totally full up. Please can anyone tell me whether this is normal? And can anyone identify the widget that was inside the pipe? I attach a photo of the metal pin and one of the fragments /wedges. Hopefully you will be able to make out the channel on the fragment where the pin once sat (or at least it seems to fit there) To my shame I had to fish these out of the bin, having thrown them away in a fit of mechanical disillusion, so sorry I haven't found the others.

Thanks in advance,

Will (see signature for engine type)

[ghost123uk]

After removing it, filling the system and bringing up to temperature, the top up tank seems now to be being filled up by the expansion tank, which is totally full up. Please can anyone tell me whether this is normal?

Yes, that is how it's supposed to work, so that is good
If you have fixed the leak, then previously it will have been sucking air back in as the system cools down, instead of sucking water from the "top up tank" behind the number plate.

I cannot think what the ,metal bits are though There are no pressure / one way valves in the system.

[petethefeet]

As a wild guess as I have an air cooled van, is it a temperature probe that was fitted under the edge of a hose???
I had a car that I retrofitted a rad fan, it was controlled via a capillary temp switch that was fitted bu lifting up the end of a hose on a stub pipe, putting a thin wire probe in and using a thin profiled rubber packing piece to stop it leaking and clamp it down with a hose clip,from Kenlowe I think.
Looks very rotted

[Tabwela]

Thanks for these responses. We've since discovered we have much bigger problems than we'd hoped - leaking water jacket seals. Now looking at a full engine overhaul. Ug.