What do you call this part?
 

So it reached 106 today here in my area in Texas. I pulled my 2007 Silverado into the garage and went inside. When I came back out coolent was all over the floor. This part had split and I tried researching this part but no luck. Looks like a rubber nipple on the radiator with a clamp. What is this part called and can it be picked at a local auto parts store. Thanks everyone

i had the same problem when a plastic part snapped off my heater core then i lost all my coolant and noone knew what it was and a dealer tried to charge me 90 dollars for a piece of plastic so i just said screw it and rigged it on there and i haven't had any problems

see if you can get the part off and get a better picture of it if possible

Thanks Wiked,

Still too hot to try and remove especially outside, will attempt this evening. Seems to be a simple rubber cap no bigger than a thimble with no hoses attached on the passenger side of the radiator. So small yet disables my truck.

So I removed the part and this is it. Such a simple piece. I need to do a Macgyver, anyone have an idea of fix to get me down the road from maybe things in my garage?

it looks like just a fancy rubble nipple plug?

or is there more too it

Any auto parts store should have that. I have always called them a heater hose block off cap. Look in the HELP section.

So after visiting the Chevrolet deal part dept the guy had no clue what this part was even looking at the schematic on his computer. Then after talking to co-workers and researching for 42 min came back stated now we know what it is, but we are out of stock.

Went to Autozone they have them and are called vacuum caps on the package. But the quality seems sub par to the original, lets hope it holds. Will be thinking of a better solution in the mean time. Really appreciate everyones help here.

The oem parts always seem to be a little better quality than the after market stuff. Any GM product dealer parts department should have them.

Another solution that worked for me is to shop around for another rubber cap that will fit snugly over the one you just purchased. You will then have a safety valve.

You also might want to buy and extra and throw in in your glove box.