T5 Water Tank Vacuum

[356DNA]

I filled the water tank today on my t5 SE for the first time since I bought it at the start of the year. Mainly to check everything was working but also to run some milton through the system.

When the tap had run for for a few minutes the water tank a vacuum was created - i noticed as there was a hissing noise from the rear and this was solved with another hiss when I opened the filler cap again. I guess there must be a one way air inlet valve and mine isn't working.

Can someone let me know where the air inlet normally is for these? On the filler cap or somewhere else?

Many thanks
David.

 

[WelshGas]

I filled the water tank today on my t5 SE for the first time since I bought it at the start of the year. Mainly to check everything was working but also to run some milton through the system.

When the tap had run for for a few minutes the water tank a vacuum was created - i noticed as there was a hissing noise from the rear and this was solved with another hiss when I opened the filler cap again. I guess there must be a one way air inlet valve and mine isn't working.

Can someone let me know where the air inlet normally is for these? On the filler cap or somewhere else?

Many thanks
David.

This might help. Parts 17 to 34.
I bet the vent tube 34 is kinked.

 

[356DNA]

Thanks. Will investigate that.

 

[356DNA]

50% solved...

The vent pipe was kinked and when disconnected released the pressure but unfortunately it still pulls vacuum now it has been unkinked... It seems to connect to the water entry fill hose via a connector but unless the cap has a one way valve in it this seems problematic.

Can anyone advise where the pipe should go to and if the cap has a valve in it?

Thanks again.

 

[TripleBee]

Isn't there a blocking in connection to the outside?
What happens if you blow through?
There is nothing blocking between the tube and the tank?

 

[356DNA]

Seems likely. I just wondered where it was supposed to vent to? Going back into the water inlet tube is what it looks like - it’s quite hard to tell due to access. This would surely create a closed system?

I’ll try running some air down it when permissions permit.

David.

 

[jts46]

Is the tank cap a genuine one?

 

[TripleBee]

I think this should be the air vent:

 

[Beeechke1]

Seems likely. I just wondered where it was supposed to vent to? Going back into the water inlet tube is what it looks like - it’s quite hard to tell due to access. This would surely create a closed system?

I’ll try running some air down it when permissions permit.

David.

Have you removed the plastic panel at the back of the wardrobe? This gives much better access, this is how I replaced the external body plate (item 30 in #2)

 

[356DNA]

Thanks for the input so far. I can confirm that the pipe is now patent, the vent back to the filler neck is clear and still the tank ends up under vacuum.

I have a STS cap which I think is OEM but not sure of this. Again, the pressure is released when I either disconnect the vent hose or open the filler cap.

I’m thinking that there must be a valve in the cap that’s not functioning but would appreciate thoughts before a bit a new one.

Cheers.

 

[356DNA]

This is the filler neck fitted to the Van. There seems to be 2 types of filler neck - mine is a 2008, 58. Could it be that I have the wrong OEM cap as the picture above shows a different style of filler?