What's This?????
 

Changing coolant today and when I removed the radiator cap I found two rings laying inside on top of the core. They look like some grey RTV and are about 1 1/4 " in diameter. Any idea where they could have come from? I stopped by a dealer today and the Service manager and Parts manager neither could identify. Looked at a new radiator cap and they did not come from there. So any ideas?

Looks like what's left over of the reinforcing loop that's in the lower hose.

Crawl under and squeeze the lower hose and see if you feel any lump or debris. There's usually a ring of plastic in there to keep the hose shape, if you don't feel it then you probably just took pictures of it.

but then again, that's rather small to be that.

Reinforcement ring is still there. Also it is a spiral, these are two rings. Pulled the water pump and no debris there. Clean as a whistle. Will pull the thermostat this morning and see if anything is visible there. Still wondering.... what is this?

Now when I look at it, I'd say someone used too much sealant on something and the excess dried and eventually broke off. But I can't think of anything off hand that's 1 1/4 in diameter that someone would use sealant on.

Did you buy this truck new?

Kinda looks like someone was storing a couple of condoms in there lol.

1 1/4" diameter, no one in my family! :)

Pulled the thermostat and hoses today and replaced. All clean, no signs of any other debris. Guess it will remain a mystery!

Thanks for the replies.

I was going to say that, but I knew someone would beat me to it...

Ahhh, yes what could be a better place to store rubbers other than the expansion tank??? Haha really have no idea what that could be