Multivan Turbo noise

[Ivo]

Finally heard my turbo spool up the other night. 6th gear at about 90km then squeeze on the accelerator and I could hear it wind up. It was fresh tarmac so no road noise.

Has anyone fitted a popoff valve like all the boy racers have on subarus etc. Not sure it would work on the bus though but would be good for a laugh!

[Silver Caravelle]

I am not sure a pop off valve works on one of these machines.

Incidentally after a good fang on Sunday, I got home only to notice the engine doing the same occasional rough running as I have mentioned before. It is only noticeable in neutral when revved at about 1500 to 2000 RPM, the turbo whooshing noise is apparent and the engine is fluttery.

I have been reading a fair bit about the EGR's and ACTIVE DPF regeneration. I have put it down to the computer kicking in the turbo to force some exhaust gas through the intake for ERG at a certain exhaust gas temperature to assist and DPF active regeneration functions. I suspect after a highway run and crawling back into the city and pulling up in the driveway, that the above was occurring to complete the DPF regeneration. After a little while, it is all back to normal again.

Apparently DPF regeneration be it active (low or no load conditions - activated by the engine computer) or passive (high load highway conditions - activated by exhaust temperature) occurs quite often.

As mentioned no fault codes were previously found by the dealer.

Does this makes sense?

Regards,

Scott

[Silver Caravelle]

This is not a bad thread on this forum regarding Active DPF regeneration and sort of explains what I have experienced, including the 'cold' regeneration cycle. I also believe a constant turbo boost pressure controlled by the ECM also plays a part in the active DPF regeneration process, hence the additional turbo noise experienced when stationary in neutral during this process.

Regards,

Scott

http://www.vwwatercooled.org.au/newf...f+regeneration

[thevwbug]

Hello Guys My Multivan 2,000 KM was suffering the same noise turbo noisey when you back off. As suggested it sounds like blow off or bearings. Picked up local VW Mechanic to go for a spin. It was in the next day apparently a leaking delaminated hose.
Going well now.

[Silver Caravelle]

Hello Guys My Multivan 2,000 KM was suffering the same noise turbo noisey when you back off. As suggested it sounds like blow off or bearings. Picked up local VW Mechanic to go for a spin. It was in the next day apparently a leaking delaminated hose.
Going well now.

Hi there,

Apparently the 'blow off' noise is normal, not withstanding any turbo hose leaks; which mine does not have.

The periodic turbo noise heard in neutral, I have concluded as part of the DPF active regeneration process, which is triggered by time and distance and driving conditions. It stops after about 15 to 20 mins of driving and will likely reoccur again in a couple of weeks.

Regards,

Scott