Sagging Roof bellows in hot weather - experiences

[WelshGas]

My 73 plate T6.1 does. Happened last night and does quite often. I have noticed times when it doesn’t, I put that down to me turning the vehicle on and off rather than just turning up and turning the van off then taking the keys out. I’m always forgetting the roof needs the keys in and ignition on to raise it. Not sure if that’s why it hasn’t auto corrected some times.

Normally the retensioning occurs 10 hrs after last Ignition Off.

 

[sidepod]

I suppose it depends on the cause of the sag. If due to fluid loss or a faulty valve then the sag would be progressive over time.
But if due to pressure relief due to high daytime temperatures and cooler nights then one would expect the pressure in the system to increase when the temperature rises , reducing the sag, and sagging again when the temperature drops. Unless the high temperature is greater on the 2nd day , producing a higher pressure and thus activating the pressure bleed valve, the degree of sag should be unchanged in the evening.

So up and down like a yo-yo, day to night. It doesn’t. Once the sag sets in, it just keeps going.

 

[sidepod]

My 73 plate T6.1 does. Happened last night and does quite often. I have noticed times when it doesn’t, I put that down to me turning the vehicle on and off rather than just turning up and turning the van off then taking the keys out. I’m always forgetting the roof needs the keys in and ignition on to raise it. Not sure if that’s why it hasn’t auto corrected some times.

Did you happen to note how far it had sagged when the auto-correct operated?
For example, had the upstairs lights stopped working due to sag?

I’m trying to ascertain what the software uses to determine roof movement. Either failed roof lighting or ram position sensors. It may well be the same thing, the sensors deactivating the lighting?

 

[DianeM]

24 plate Ocean, We are currently travelling and the roof sags on the passenger side almost everywhere day, doesn’t have to be that warm. Hubby is a hydraulic engineer and says this definitely shouldn’t happen either the seals in the ram or the check valve aren’t working, diggers can sit for weeks holding great weight and don’t creep down. We are still travelling but will be. He getting very annoyed

 

[sidepod]

24 plate Ocean, We are currently travelling and the roof sags on the passenger side almost everywhere day, doesn’t have to be that warm. Hubby is a hydraulic engineer and says this definitely shouldn’t happen either the seals in the ram or the check valve aren’t working, diggers can sit for weeks holding great weight and don’t creep down. We are still travelling but will be. He getting very annoyed

I’m glad finally someone in the know pointed that out.

 

[DianeM]

I’m glad finally someone in the know pointed that out.

I should also say we have previously owned a 19 plat T6 and didn’t have this issue. I’m getting the blame for pushing for the new van, he had a list of dislikes compared to the T6, something dodgy with the sliding door lock too we were locked in the van yesterday had to put the window down and open it from the outside. I won’t list all his complaints

 

[Betsycalifornia]

Did you happen to note how far it had sagged when the auto-correct operated?
For example, had the upstairs lights stopped working due to sag?

I’m trying to ascertain what the software uses to determine roof movement. Either failed roof lighting or ram position sensors. It may well be the same thing, the sensors deactivating the lighting?

Lights out, they went out as we went to bed and the autocorrect kicked in during the night.

 

[Oceandrive2023]

Lights out, they went out as we went to bed and the autocorrect kicked in during the night.

Interesting ! Can't understand why I was told that T6.1 don't have auto correct .

 

[sidepod]

You could try to provoke an auto-correct.

Ignition on, roof up, upstairs lights on.
Close the roof until the lights go off.
Ignition off/key out
Wait 10hours.

 

[vbk1975]

You could try to provoke an auto-correct.

Ignition on, roof up, upstairs lights on.
Close the roof until the lights go off.
Ignition off/key out
Wait 10hours.

I have been trying to work out the auto-correct for the T6, i can't state for sure, but I think the system is looking for one of the fully open sensors to change from open to not-open after the system has driven the roof to open (and seen the electrical load on the pump that indicates it has been fully pressurised.) , this check happens after X hours from ign off and I assume just drives the pump until it sees the sensor change and pump electrical load spike. But having had a look at the roof symbol vs the roof drop, it is a reasonable drop for the sensor to change from open.

As per your suggestion above, so i think if you command the roof closed even a little bit, then the system won't try and auto-correct, but i might be wrong.

 

[WelshGas]

You could try to provoke an auto-correct.

Ignition on, roof up, upstairs lights on.
Close the roof until the lights go off.
Ignition off/key out
Wait 10hours.

Why would they change the system that triggers the auto-correction for the T6.1.
The T5/5.1 doesn’t have roof lights and auto-corrected.

 

[Hawthorn37]

We also have a sagging roof, that happens when the roof has been up for around 18 hours. We need to manually lower the roof a bit, and then raise it. I was under the impression (from the handbook) that auto correction would tension the roof. It doesn’t happen for us.

 

[CaliforniaCylus]

The auto correct works seemlessly when you leave the vehicle alone. Put the roof up, take the keys out and at 10 hours it will re-inflate if necessary. And then at every 5 hours. Once it doesn't need to correct it never checks again.

Whilst not documented, the timer appears to be disabled by turning the ignition on. I think there are other functions that also cause this reset.

I think the TPI is documented in this thread in that the roof has to fall 20cms in 72 hours. Of course leave the vehicle alone and it auto corrects so you never meet the VW criteria. Unless it's massively broken.

Also I think autocorrect only kicks in at the point the lights switch off. So if they switch off at 10 hours and 1 minute, no re- inflation.