Passat TDI130 engine roar at 1300rpm

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Sat 31 Mar 2007 14:27
Passat TDI130 engine roar at 1300rpm - carman
Hi all

I have a passat tdi 130 (May 05, not the latest model, the one before) that has done 19500 miles, and in which I've done the last 10000. Ever since I bought it there has been an easily audible 'roar' from the LHS of the engine compartment (seems to be from there at least) as the engine passes through 1300rpm under load, not necessarily foot to the floor. Does it in any gear, but most noticable in 3rd or 4th when picking up speed after going round a slow bend for example, or just keeping up with gradually changing traffic speeds. Its a kind of low-frequency growl, as if something large is vibrating quite heavily and is worse when the engine is warmed up. Been in the garage 4 times now and they've tightened panels, changed the air box, put felt under panels but to no avail. Had a 'new' Passat tdi 140bhp all this week while it was in for checking and this does not growl.

Anyone experience anything similar?

I have a feeling the garage will say they're unable or unwilling to take it any further and I will have to find a way of proving it's a fault. Is there recourse to a 'higher level' of investigation in VW I could demand they contact if this happens?

Any thoughts appreciated

Thanks
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Sat 31 Mar 2007 14:35
Passat TDI130 engine roar at 1300rpm - Hamsafar
Does this car/engine have a viscous fan mounted on the engine? I think so, because it is a longitudinally-mounted engine.
These can make a roar noise in the circumstance you describe, until they reach a speed where the drag on the fan causes the viscous coupling to slip. The easiest way to tell would be to take it off and try it for a few days.

See www.kenlowe.com/fans/consumers/fans03.html
under the heading LESS NOISE for more info.
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Sat 31 Mar 2007 14:48
Passat TDI130 engine roar at 1300rpm - carman
Hi Ashok

Don't think it's the fan. The noise is only apparent as the engine goes through 1300rpm, and therefore is directly related to this engine speed. It's also related to the 'load' the engine is pulling. No or little load, no noise. put your foot down a bit and the growl is audible. It's more like something's loose, but the garage seem to have checked all that kind of thing. Exhaust? Turbo maybe?

Carman
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Sat 31 Mar 2007 18:15
Passat TDI130 engine roar at 1300rpm - craig-pd130
Check the fit of the intake snorkel on the airbox. These pop loose easily off the mouth of the airbox and make a loud and intrusive resonance at low rpm, especially under load. There's a handy bolt just above the snorkel that's ideal for wedging a blob of blu-tak underneath to stop this.

Also check the fuel pipes which pass very close to the bulkhead, mine rattled against the bulkhead and took me AGES to track down, but only a coupla minutes to sort out.
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Sun 1 Apr 2007 12:32
Passat TDI130 engine roar at 1300rpm - 659FBE
I would second Craig's suggestion concening the intake/airbox assembly. I think it's prone to resonate at caertain engine speeds and is not a particularly good fit. I have found that a few strategically positioned cable ties can keep it quiet - be careful not to damage the MAF sensor.

659.
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Sun 1 Apr 2007 13:17
Passat TDI130 engine roar at 1300rpm - milkyjoe
have you got a tiger in your tank?
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Sun 1 Apr 2007 13:32
Passat TDI130 engine roar at 1300rpm - carman
Hope not! Wasn't that a petrol advert?
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Sun 1 Apr 2007 13:30
Passat TDI130 engine roar at 1300rpm - carman
Hi Craig

Just tried wedging kitchen roll around the air box to stop it vibrating but the problem persists. Not sure which are the fuel lines - are they clearly visible as you look into the engine compartment from the front? None of the pipes I could see and touch that are up against the bulkhead (at the back end of the engine bay ?) seemed loose though.

The growl seems 'weightier' than the noise I imagine a narrow pipe vibrating would produce. Like it's something big that's vibrating on the left side as you sit in the drivers seat. What's down that side anybody? - I don't know my way around the car! Exhaust, Turbo?

Thanks
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Sun 1 Apr 2007 21:40
Passat TDI130 engine roar at 1300rpm - Andrew Moorey (Tune-Up)
A while ago I had a similar experience with a 1.9 Audi A6. Turned out to be the freewheel clutch on the alternator had siezed causing the alternator belt to resonate. The belt could be seen to be vibrating until the revs were picked up.
Andrew
--
Simplicate and add lightness!!
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