expansion tank hose, part number or replacement idea

[426speed]

2002 Audi S6 4.2, 6 speed swap.

The hose that goes to the expansion tank is leaking. There isn't an OEM or even aftermarket replacement that I can find. I can't even find the OEM part number or a diagram to figure out which hose. I'm pretty sure the issue is there is a snap lock on one end.

Can someone give me the OEM part number or a diagram with part numbers?

What's the usual solution for replacing this?

[Audibot]

Which hose? The diagram I see for it shows 2 hoses.

One is the upper hose that inserts into the reservoir at the back with an angle towards the front driver's side and goes into the rear coolant pipe and has a hose to the upper radiator hose. This hose is 4B3121107D.

The other looks to be below that and connects to a pipe that runs down the V of the engine. This is 4B3121109.

It looks like the snap lock is related to this hose, which comes up as part 4D0133335 (coolant sealing cap). Or did you mean a c-clip like a coolant temp sensor?

[426speed]

That's amazingly helpful, thanks. I think the one that is messed up is the upper hose with the tee. On the OEM, it's a molded tee, of course. Looking at this it seems like the molding doesn't matter, there's not enough pressure.

[ShelbyM3]

That's amazingly helpful, thanks. I think the one that is messed up is the upper hose with the tee. On the OEM, it's a molded tee, of course. Looking at this it seems like the molding doesn't matter, there's not enough pressure.

While I don’t have an S6, I’ve seen this topic discussed in C5 Groups on Facebook. A lot of people have replaced the reservoir with a different VAG unit and/or used an extra long bulk hose that they have routed differently. If I’m not mistaken, the S6 reservoir is unique even to the RS6 one. I think you can make an RS6 one work, but don’t quote me on that. If you’re on Facebook, search for the Audi C5 Group group and you’ll probably see the posts there. A couple different pictures were posted, also.


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[ShelbyM3]

https://www.facebook.com/share/p/1GBySX15Mn/?


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