Top end engine rattle after Emissions Recall

[Motorway]

Our 2011 Passat Estate 2.0tdi 140 Bluemotion was in for service the other day. it was only an oil service and pollen filter change. i had also got the letter inviting me to have the emissions recall done.

before the car went in it was running great with no issues, and i did wonder if it was worth having the emissions recall work done. but the dealer assured me all the bugs had been sorted out and i should see no difference to the car. initially i did not economy did seem to be OK, about the same on local miles. not done a long run yet so cannot comment on that yet. however the engine did sound different straight away as soon as i drove out of the dealers. it was a hot day and aircon was running, the difference was a deeper exhaust note, similar to when the DPF is in re-gen mode, but without the increase in engine speed and cooling fan.

now the weather has cooled to the normal british summer temps aircon is not running as much and another noise has been noticed, it sounds like tappet noise. when you change gear in accordance with the shift change light the revs drop to approx 1200rpm you hear this tappety noice until the revs pick up to 1500approx. this noise is most noticable in town driving when you change from 3rd to 4th with a road speed of 30mph engine speed is just below 1200rpm and with light throttle the tappety noise is constant. with more throttle even at the same speed, i.e pulling uphil the noise goes away.

i have checked oil levels all OK and remover oil filler and plenty of oil is reaching top of the engine, i have also checked drive belt tension just in case the belt was slapping at this low speed (had this on a Landrover discovery).

as the service was just Oil filter and pollen filter there is nothing that the service routine could have done to make this change. the tappety noise was not there before the service. so i can only assume that the emissions recall (software update) must have caused this. does any of the knowledgable people know exactly what is adjusted on this software upgrade. my opiniion is there is some change in injection timing or valve timing or a combination of both to cause this noise. i could do with a bit more information before i go back with the car to the dealer.

any coments / help would be most appreciated
thanks

[martin1810]

until someone posts an emissions recall changed ecu file on line it is impossible to know what changes have been made. In theory the changes should have no effect at all as they were meant to remove the "test cheat" part of the file.

[rowdy-999]

Has it not mentioned on here, that to reduce the NOX levels they alter the engine timing? I'm no expert on diesel engine timing, but I assume it could make the engine sound and run different.

Other than that it could be as simple as a loose fitting engine cover or other component?

[Gazwould]

The engine is retarded to produce less NOx , as diesel has an ignition delay anyway further retarding will cause diesel knock .

[rowdy-999]

The engine is retarded to produce less NOx , as diesel has an ignition delay anyway further retarding will cause diesel knock .

So you're saying the recall can cause extra 'knock'?

[Gazwould]

Yes , heard this problem with others .

Vag are not consistent , they're doing a better job on some
engines than others , effectively your car is a guinea pig .

[Motorway]

Thanks all for the replies so far, if the engine has been retarded to reduce the Nox, then am i likely to notice a reduction in power, i have only driven 150 local miles since the service and recall. for the last week i have been driving my Landrover discovery so the passat has been just used locally. but have a holiday towing caravan later this month so a reduction in power would be noticed then. the knock is noticable at 55mph in 6th gear which is my average towing speed, is the knocking likely to cause some wear?. especially with the extra load of towing for 8 hours at motorway speeds. or am i better off taking car back to VW and get them to alter the settings?. if they will or can?

thanks again for your input

[Alltrack]

The B7 Passat 2.0 TDI has the EA189 engine that was fitted with an 'acoustic device'.

This 'acoustic device' was originally developed by Audi for the 3.0 V6 diesel engine. They realised that they could get rid of the characteristic diesel clatter by injecting a bit more fuel into the engine upon ignition. The trouble was that this increased emissions considerably. This was then used with the 'defeat device' to identify testing scenarios. VW then adopted this 'acoustic device' on to the EA189 engine. Obviously new models (B8) do not have this.

A friend of mine had his 2014 Tiguan 2.0 TDI modified as part of the VW emissions recall. He is not happy at all as he thinks the diesel clatter has increased enormously. It seems the modification on the 2.0 TDI EA189 is just a software update, presumably where this 'acoustic device' is removed.

I actually took him for a drive in my B8 2.0 TDI and he noticed the same clatter noise on my engine. Personally I don't see it as an issue as I had a Mondeo 2.0TDCI prior and it made a similar engine noise (clatter) to my B8.

On another VW forum a user was complaining about the extra clatter that the 2.0 TDI in the B8 makes compared to his B7.

[UMEL]

The mod is not compulsory so I am coming to the conclusion that I will not have my car altered. I like it the way it is.

[cruise control]

Hello guys.
i wish i had read this post last week... had my passat serviced this week and had the emissions recall done at the same time. i thought it was good for resale if the recall had been done, the dealer assured me that all of the early problems with the software had been ironed out, so i agreed to it..... big mistake...

firstly i have the increased clattering noise which as Motorway said i the initial post seems to be from the top end of the engine (Tappets) at approx 1200rpm in any gear, although once you get into 5th road noise masks the clattering. also power seems a little down in the lower rev range, we have a hill near home that normally i can go up in 5th at 42-44mph. since the recall i have to change down to 4th to keep up 42mph. MPG does not seem to be affected.

as Motorway mentioned i am a little worried about engine wear whilst the clattering is happening, i too tow a caravan and we are heading to spain in 10days time as motorway said towing at 55-60mph in 6th gear is within the rpm range where the clattering occurs. we have 3000 miles of towing during the holiday so dont want any problems.

what would be the best outcome for me would be if the dealer could return the software to pre-recall version. does anyone know if this is possible and if so would the dealers be willing to carry this ot for me. any help is very much appreciated.