A new mystery need so be solved

I found this part on the back of the termostat housing with one of the vacuum hose disconnected.
What is this part do??? and does the other hose should be connected ?

The part you are worried about is a thermal valve that allows a vacuum signal to operate the carbon canister/ purge system for emission control. There should be two hoses connected to it.
As an aside, and this is just based on my own past experience, consider taking the ring off your finger before working on the car. Good way to get hurt.

Mine actually just broke at the base of one of the nipples. Havent had any luck finding one so I ordered an identical looking one from fcp euro with an Audi/vw part number. Fingers crossed! And what @DavetheLimey said is correct. I’ll add some pics of what that goes to. Keep in mind mine has a cap on it at the moment due to the line breaking. The other line runs down with the rest of the hoses to the charcoal canister.

More pics…


Amazing what some color will do to that v12 engine bay. I can stare at your engine all day. When it’s just a mess of all black hoses and wires, its so much less interesting.

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Where do you get colored hoses

Here you go.

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Thanx… will look into it

Im planing to replace my vacuum hose too, do you have the vacuum line’s diagram ?

What year is your car?

Hey ,
I have a 1988 v12


There’s some good links here.


I went here cause I liked the yellow…

Oh, and they sent me a sample to make sure the yellow was what I wanted versus that neon yellow.

HPS is great also! I have a couple of their blue coolant hoses which I tried out. Thinking about doing all the lines with their blue hoses if I can get the right hose config.

@Pirk very nice! I like the look of the blue!