406oc.co.uk

Hello everyone. Sorry haven't been around - just very busy with.. well, life really!

I have a question, of many, about what could be causing the build up of soot in the engine bay. I cleaned everything and the soot *seems* to be coming from behind the engine, to the left of the EGR valve/tube thing. There's also a rumbling noise when accelerating and even if I just rev and listening in the engine. Sounds like a whole/crack somewhere but not sure where.

I intend, weather permitting, to crawl under the engine and have a good look with the engine running but when I did the service last week, I didn't see anything out of the ordinary. But need a cold running engine so I can feel for escaping exhaust gases...

Could it be the exhaust manifold? Or some other piece in the downpipe assembly? Space is limited there and difficult to look inside. The flexi section seems intact and no soot on there so I think it's somewhere higher up. There are no funny(?) exhaust smells in the car, like I had when the flexi was torn...

Ideas?

I'd put money on the exhaust manifold gasket, or worse yet a crack in the manifold. Seen a few of them go but never on a 406...

Honda diesels suffer terribly and expensively from the exhaust manifold cracks. Hoping it's just the gasket but will have a poke when I can.

If it's near the egr then I'd have thought that was choice Especially if it's been disturbed...

Sounds obvious but I don't think that's where it's coming from. I'll take an take a picture tomorrow.

You can see the soot around the join but there's soot everywhere around that area. What's the cylindrical bit?

I had a poke a around with a cold engine running but couldn't see anything obvious. Couldn't really see the exhaust manifold either - need to try and look underneath over the weekend. However, I could smell the exhaust fumes coming... from somewhere. Wasn't strong and I had to poke my head right in the back of the engine bay....

Any ideas?

Fire up Service Box and look for:
1628 KC WATER EXCHANGER DIAM 54

Perhaps the collar is leaking? On my 2.1 you had to cut them off and replace with a hinged one that does up with a screw but it looks like that's what they are now.

Hm maybe. What's the function of the water exchanger other than the obvious.....

If it helps, I disconnected the EGR vacuum tube last year - could this have something to do with it? Maybe just needs a nice blow out.... Also! Where to people put the 10p to completely block the EGR?

The best way is to get a smoke test done - they pressurise the whole system with white smoke and watch for leaks - my egr system was pissing out and I too had the smell going on.

Dirty EGR:


Dirty EGR:


New one in place, the by-pass tube is a pig to seal properly (that corrugated tube bit).


If you've effectively cut yours off I reckon it's blocked with soot, which is causing pressure and forcing it out from that joint. Your experimental re-mappage would have caused sh*t loads of soot in this system. I think you should replace the EGR and associated pipework and leave it operating as it should do (it closes when your on the throttle anyway )

Ah interesting. Should get that smoke test done then. But first... is it possible to clean this EGR or is it just better to replace it? Maybe in the process, I'll be able to reseal any joints.

Farmerpug cleaned his and did a Video too I think? be worth checking on here (I can't be arsed to search for you ).

Looks like this one - http://www.youtube.com/watch?v=wa3OeeKmSOU&feature=plcp

Maybe I should just blank it.... Looks like I cannot remove the water cooler thing as it'll spill water all over the shop. If I move it out of the way, I am hoping I can get to the exhaust manifold and replace the gasket - in case that's leaking. That should (hopefully) keep most of the fumes out of the engine bay. Will need a proper look-see under the car though.

Does that have the exhaust gasses recycle through it and coolant round the outside?
Not looked at a 2.0 for a while but the 2.2 is similar i believe

Yep, correct.

On the coupes I saw last Sunday it looks like they
* blank both ends of the EGR
* remove the recycle pipe
* leave the water jacket
* bung the vac pipes

Finchy is the expert on removing such superfluous plumbing: EGR, and air dozer (which is used for FAP regen -- so doesn't bother us).

They report that after removing the EGR your engine oil will become a lot cleaner.

This post on PeugeotForums which explains the intended operation of the EGR, make me think that it's better to have a working EGR than a removed EGR.