Hi everyone,

This is my first posting. Have found lots of useful info already just by searching existing threads - great forum.

I've had my Octy vRS TDI since may (build date 5th Feb), and so far have had most of the 'usual' issues; e.g tapping rear seat catches, dashboard rattles and noisy climate control.

None of these are major and I feel they don't spoil the enjoyment of the car.

Unfortunately I have also started getting a much more serious 'tractor' noise and stuttering for some of the time.

The loud engine noise occurs on part throttle acceleration, i.e. when depressing the accelerator lightly or hovering on the throttle at around 1500 rpm, especially in 2nd/3rd gear. It could be described as a tractor/transit van - its LOUD!! And embarrassing

There is stuttering and harsh power delivery at the same time as the noise.

Becomes very juddery at idle. Feels like the car is going to stall when sat in a queue.

It is intermittent. On average once a week since we got the car, but the last couple of weeks seems to be getting worse.

No pattern - happens totally randomly, usually when the engine is warm and has even happened straight after a long motorway run.

Will sometimes stop for a while if I restart the engine. Once had to restart 4 times and the car was virtually undriveable because of the erratic throttle response.

Because no fault codes are logged and the car hasn't made the noise while at the garage, my dealer has so far not been helpful. I am taking it in again this week.

The only mention of it I have found on Briskoda is here: http://www.briskoda.net/forums/new-octavia/pd170-vrs-engine-problems/83976/ and mainly discusses stuttering rather than the noise.

If you look on the Audi forum http://www.audi-sport.net/vb/showthread.php?t=37777 you can see how common this problem seems to be in the PD170 engine.

I would really like to know if anyone else with the vRS TDI is suffering this problem, and also if anybody has opinions on what could be causing it they would be much appreciated.

Thanks in advance

That is the tribute you pay for doing something good to the environment.

It is your particular filter that does its cleaning job. It is regenerating because it was full.

Extra dieselfuel is injected to get hotter combustion. At higher temperatures your filter can be burned clean.

It does it once in a while when the filter gets full. When depends on how your driving (if your doing citydriving most of the time, the regeneration-proces will occur more often).

Hi there, I'm sure we would like to help but a bit more info is needed. A couple of questions;-

1. What is your average weekly/monthly mileage?

2. What is your typical journey length, speed etc

3. What fuel do you use? Supermarket, Branded or Premium?

magic62 suggests it is the DPF regeneration cutting in to do it's clean/purge/burn out cycle that sound very plausible, but from what I have read in the handbook, there is a little tell-tale light on the dash/speedo to indicate this. I'm not completely sure about this, as it hasn't come on for me at all in 6500 miles, so may only be a 'fault' tell-tale light i.e. when it is 'blocked'.

The PD170 engine can sound somewhat 'tractor like' as a result of the super high pressure PD fuel injection with uprated (over PD115/140) piezo injectors and it is quite sensitive to the fuel used. Premium fuel i.e.Shell V-power/BP Ultimate is know to give smoother quieter running vs. Supermarket/Branded.

Food for thought?

Thanks for helping out guys.

I do about 13-14k miles a year, with the weekly average being a 28 mile round trip to work every day during the week (b roads and stop/start driving) and the rest made up on the motorway at weekends as we have family living miles away and go on holiday a lot during the summer.

I tend to try to use Shell diesel extra, only fill up elsewhere when it desperately needs it. I had actually thought that maybe it ran a bit worse when I filled up at a supermarket so you could be right there.

The thing is that I don't understand why it would be going into active generation so often - 4 times in one week :confused: - especially when it should have been cleaned through passive regeneration on the long motorway runs. It sounded like a tractor a couple of days after a 160 mile run. The DPF light has never come on to suggest that the DPF is actually clogged either.

I really didn't know much about the problems which could be caused by a DPF until after I had bought the car. Surely it is not ok for a dealer to sell you a car and neglect to tell you that unless you do a certain type of driving the car will regularly sound like a tractor and be really unpleasant to drive?:(

Regeneration only occurs when driving constantly between 2200-3200 rpms. Under and above it will stop to regenerate.

The light only comes on when the cycle is stopped to often.

I only use synfuel (ie Shell V Power, Excellium oder Ultimate diesel), my experience with this kind of diesel is, that it doesn't regenerate that often as when using normal derv.

Also does my motor run smoother with Ultimate than with normal diesel, especially after a cold start.

A diesel is producing more particles when used heavilly. High speed running (I guess in GB it will be not that often as here in Germany) and heavy acceleration will produce more particles as constant running at 2500 rpms. You can see that on cars without the filter.

The problems with the filters is known, not only at VAG. Other manufacturers are also having problems when the car is used a lot in city traffic (short runs).