hi im new to this site. i have recently got myself a 54 plate 535d and i am very happy with it apart from the sound of the exhaust randomly goes loud when im driving down the road!
i can be driving along (normally at low revs when it happens) and the revs start to fluctuate a bit then it goes loud.
i would be really grateful if anyone can help on here as its starting to get annoying

thanks

craig

Welcome to the forums Craig!

You don't have to worry about the sound, it's the DPF (diesel particulate filter) going through the regeneration sequence! :thumbsup:

If you go outside the car when the sound is on, you will smell like something's burning. Actually the soot is burning in the DPF as the car tries to clean the filter. To keep your DPF in good health, you should never shut off your engine when the regeneration is on. Sometimes a clogged DPF can cause power problems. Check my DPF thread here to learn some more!

Once again, welcome to the forums! :twoup:

- Antti -

Thanks for the reply. I have noticed the burning smell. If the DPF was getting old and dirty would it try cleaning itself more often? It does it quite a lot. Is there anyway of getting rid of it? Would it effect the car much if I had it removed?
The car come with an after market exhaust on so it's really loud and annoying when it kicks in. Iv had a silencer fitted to try and quiet it down but it didn't really help much.

Thanks

Craig

Often happening burning can be a sign of a clogged DPF. It can be removed though and replaced with a straight pipe, but then the car must be reprogrammed or it still would go through the burning sequence. The regeneration must be disabled in ECU, and that requires some knowledge from the programmer.

- Antti -

Hi,
I've never heard any regeneration or whatever sound coming from the exhaust. I would say that I never have been through a regeneration sequence of the DPF ('06 535D chiptuned with 200.000km)

Is this possible ?!

Hi.

If your DPF hadn't ever gone through regeneration, it would have been clogged for a long time already. Some people say they can clearly hear the regeneration and some people say they can't hear it. The original poster says he has an aftermarket exhaust system, and that can make the sound louder.

I can hear it when my DPF is going through it. In my car it's a low humming sound when accelerating.

You can follow your engine temps in a "hidden menu". When the regeneration is on, the engine temps go up about 4-5 celsius degrees.

- Antti -

would it effect the performance any if i had the DPF removed? it is a low humming noise when it kicks in but with the after market exhaust its a very loud and anoying humming noise :thumbsdown:

which DPF would my car have? as i think there is a choice of 2 isnt there?

thanks

craig

Removing the DPF would affect positively the performance :thumbsup:.

Yes, there are two kind of DPFs (depending on the model year);
- those who are in a same can with the catalytic converter and are located right after the turbo
- and those who are in a separate can located under the car

I'm pretty sure 535d has allways have the separate can version. Another member is struggling at the moment with removing his DPF in his 535d --> check the thread behind the link I gave.

- Antti -

i have seen under the car when i had the silencer fitted and the only box's left on the exhaust were the rear silencer and a big one on an angle just after the turbo. i think that may have been it but i was unsure, does that sound like it to you?

would that be the all in one box with the cat and the DPF?

thanks

craig

Hmmm...

What model year is your car? I can't read the "54 plate" language :D.