Intermittant engin noise

[dave.sweetman]

Hello! I have a 2007 2.0 TDI DPF (170) Dsg. At least 1-2 times per week, my engine goes through a phase of sounding rough! Normally, when revving or accelerating, my diesel engine purs when I pull away. However, over the last 12 months, this puring turns to a "lumpy old diesel" sound?

I do mainly motorway mileage with the odd bit of around town driving. I have had the DPF light on once which I cured by following the manual instructions, but seem to get that excessive engine noise come back with no dash warning!

This noise does eventually go away by itself, however If I follow the DPF re-engerizing procedure, the noise does go away a little quicker. But it seems to come back!

I have taken the car into the dealership a few times with this problem, but have had no joy.

During its rough period, I do get a burning smell from the back of the car!

Has anyone got any ideas, or information that can help me?

Regards

Dave

[johnloaderuk]

It sounds as if it's just the DPF regenerating itself. The warning light should come on only when it gets too blocked, and usually the engine runs slightly differently during the regeneration process.
There may be another problem, but from what you describe it sounds perfectly normal to me.

[ledburyloafer]

I don't get issues with teh engine, but often can smell a burning coming from the back of the car, like rubber, would that be caused by the DPF?

[johnloaderuk]

I don't get issues with teh engine, but often can smell a burning coming from the back of the car, like rubber, would that be caused by the DPF?

Yep. I don't know the exact temperature at which the DPF burns off deposits during regeneration on a VW, but many of them go up to 600 degrees celsius internally, hence the burning smell.

Some of the early X type Jags with DPF had poor heat shields around the DPF and if parked up during regeneration the car could catch fire due to the heat - not good, and not something I've heard of on VW's - yet.