Multivan Turbo noise

[BobD]

No worries, Scott. I misinterpreted your problem as the same as mine, assuming it was rough idling, not rough slow speed running.

I find that apart from the odd times when the idle plays up, the engine runs very smoothly. By the way, even when it idles roughly, the idle speed is sopt on and never varies. It just tends to shake the car a bit so it really is rough idle. As soon as the engine is loaded it goes away and the engine runs perfectly.

[Silver Caravelle]

Hi all, Thanks for you extra feedback.

Well I am back to the drawing board again as what I have highlighted is apparently not normal nor related to DPF regeneration as it turns out.

Over the weekend and this morning I experienced the same issue - rough running at low revs ( when in neutral and not under load) occompanied by significant Turbo swishing/wooshing noise. The Turbo swishing/woohing noise also appears to be present at low revs in the higher gears under load. But seems fine otherwise. It seems to correct itself for a while when I restart the engine.

It is booked into the dealers next week to some fult analysis after they took it for a test drive this morning.

I will keep you posted.

Thanks, Scott

[Two Dogs]

I'm not sure if I'm interperating you correctly but if you say you turn the engine of immediately after giving it some revs, I suggest you investigate the possibility that it may harm your turbo.

I know that in times past the bearings for the turbo vanes relied on oil to operate correctly, and turning of the engine immediately after the turbo was running starved the bearings of oil. Hence the use of turbo timers in earlier times to guarantee oil delivery for a period after use.

Not sure if this is still a requirement but thought it may still be necessary. If not please disreguard.

Two Dogs.

P.S. Did not mean to hijack the thread.

[Silver Caravelle]

I'm not sure if I'm interperating you correctly but if you say you turn the engine of immediately after giving it some revs, I suggest you investigate the possibility that it may harm your turbo.

I know that in times past the bearings for the turbo vanes relied on oil to operate correctly, and turning of the engine immediately after the turbo was running starved the bearings of oil. Hence the use of turbo timers in earlier times to guarantee oil delivery for a period after use.

Not sure if this is still a requirement but thought it may still be necessary. If not please disreguard.

Two Dogs.

P.S. Did not mean to hijack the thread.

Two Dogs, Thanks. This was on a couple of short occasions to emulate the Turbo noise. The Turbo slows down very quickly in this situation, so should not be an issue.

Thanks, Scott

[Silver Caravelle]

Hi all,

The Multivan checked out OK - no turbo fault codes logged. The turbo 'shwissing noise' is considered normal and was the same in another one I drove yesterday. Predominately noticible under load conditions and low revs (and disappears after revs increase beyond say 2000 RPM). Also noticable immediately upon accelerator back during load conditions.

The rough running and associated turbo 'shwissing noise' noticed on a couple of occasions whilst stationary in neutral may be attributed the EGR kicking in from time to time. But I will keeping an eye on this.

Regards,

Scott

[gregozedobe]

IIRC the turbo vanes change from "max possible boost" to "partial boost" at around 2,000rpm (to stop over-boosting and subsequent engine damage), so that might be the change in sound you are hearing. Can't say I've noticed anything like that on mine, but I do notice the 5cyl "warble" from the injectors under load at around the same engine speed.

[Silver Caravelle]

IIRC the turbo vanes change from "max possible boost" to "partial boost" at around 2,000rpm (to stop over-boosting and subsequent engine damage), so that might be the change in sound you are hearing. Can't say I've noticed anything like that on mine, but I do notice the 5cyl "warble" from the injectors under load at around the same engine speed.

Thanks for the feedback. Regards, Scott

[BobD]

I can't hear anything from my turbo still but mine is auto so I can't give it heaps at low revs. It will always change to a lower gear at 1500 revs or more depending on load. It will only stay below 2000 under very light throttle or on over run.

My main complaint after the T4 TDI is the fuel consumption. Wheras the manual T4 would get around 7.5l/100km in most conditions the T5 auto is getting around 10.5l/100km in the same day to day driving conditions. I especially miss having to fill up at 1000km instead 650km or so in the Multivan. I keep on nearly running out of juice as it goes to empty much quicker then the T4 when the fuel gauge is low. I have put in over 84l on several occasions at different garages and the tank only holds 80l. This is not the cause of the rough running though. The rough running happens when I have used about 70l and it ran fine on the times I let it get really low.

[Silver Caravelle]

Thanks Bob for the feedback. My auto Multivan has averaged 9.7L/100Km on the trip computer (no) 2 for it's 4000 km so far.

For specific trips, it tends to average about the same with a mix of city and highway driving. I have seen about 7.0l/100km at best and over 10l/100km in a head wind and city driving.

It can be up around the 35 to 40 l/ 100km until it warms up, then it settles down to the above averages.

Regards,

Scott

[BobD]

Mine says about the same on the trip computer. This is always optimistic and if you check the km vs litres you will not get such a good reading. I usally put in around 75l after about 650 to 700km and on the T4 I put in 65l for 900 plus km. Both cars also have optimistic speedos and are out by about 6kmh at 110kmh (116 on the speedo is 110 on the GPS). I'm not sure of the distance accuracy as I haven't got around to a serious check against a GPS.

The T4 had fantastic economy and made diesel a cheap way to go. The T5 makes the extra cost of diesel of marginal benefit at most. My T5 is up to 50,000km since July 2007.