Hello Everyone.

I have a problem with my lower radiator hose on my 2000 S40 (180K miles). See the 3 photos I have attached. You will see the lower radiator hose on my car, and you will specifically see a red slotted round piece on that hose. It looks like the head of a bolt/screw. You can see that it is leaking a bit of coolant (see the water leak marks around the slotted piece). What is this red slotted piece for? I removed it a few days ago, and it seems to be just a bolt/screw that (once removed) provides access to the coolant fluid in the hose. Is this red bolt/screw used to test something? Is it to be removed for the purpose of attaching some other optional thing to my car's coolant system? Is it some kind of adjustment to my coolant system? I cannot figure out it's purpose, and my VADIS manual does not show it's function or list it as a separate part. It does not seem to have any gasket or o-ring attached to it either.

What is this thing and what does it do?

Thanks all.

 

It is a bleeder to let air out of the system. When you change the coolant, sometimes the system can get air-bound and not fill easily. You can open the bleeder to let the air out and it fills much easier.
Stan

 

You are the man, Stan. Thanks.

 

I recently discovered this same problem on my 2000 V40. Its lower radiator hose is of the URO brand and has a metal bleeder screw. Whats something good to seal it up with as my local volvo shop says that's all they would do to fix it. All I have is silicone caulking in my garage which I doubt is the right thing to use. Suggestion?

 

Permatex #2

I've used it on every water pump ever changed since about 1972.

 

Awesome. Thanks a bunch!

 

i have the same on my 2001 S40 but it seems to have disintegrated, I have recently been having some issues overheating, would it be due to a vapor lock? Could i replace it with a hose without this?