2.2 HDi 173hp Air Doser

[jml]

I’ve done a search on here and found some helpful information but I’d like to ask some questions.

On my C8 2.2 HDi 173hp I’ve always noticed that whenever I’ve either unlocked the car, opened a door or turned on ignition (can’t remember which) there’s been a slight high pitched whine from under the bonnet. I think it is also there for a few seconds after I turn off. It all sounded perfectly ok until last few days when it’s been accompanied by a light clicking/buzzing sound - there all the time the ‘ignition’ is turned on - although maybe not once the engine is running ?

I searched and located it to the unit at the top of the pipe from intercooler into the inlet manifold and, thanks to Citroen service, I identified it as the air doser.

I’ve also noticed that when I turn the engine off it seems to run on for a second or so (like some BL petrol cars used to do )

A) I think the problems are related
B) If I remove it do you reckon I’ve got any chance of cleaning or stripping it - new one’s about £250
C) Will it do any harm leaving it ?
D) I’ve just had my DPF additive refilled by a Citroen dealer (for the very first time in over 150,000 miles !!). Could this be related ?

My guess is that it’s something like a solenoid inside that’s chattering and when I turn off it should either vent to air or cut off air supply and it’s not doing that properly.

Any thoughts or advice would be gratefully received.

[GiveMeABreak]

It's perfectly normal. It is likely to be the EGR valve reinitialising its position or the air doser etc. The various ECUs write their values to memory when the engine is switched off and before the BSI shuts down the data networks.

What exactly is the issue?

On another note - although you have filled your additive tank, 150k miles is well over the life of a particle filter, so if you haven't already, I would expect you to start getting a warning at some point (unless you have had the DPF cleaned or replaced of course).

If you have any issues generally, get it diagnosed with a Lexia and report any fault codes here.

[jml]

Drat !
Thanks Marc. I wrote a detailed reply but because of poor phone signal it didn’t send and is now lost

Will try to reply again later !

[GiveMeABreak]

Ok, sounds like here - no phone signal, forget 3G, 4G and 5G - completely ridiculous. Yet they reckoned they put a man on the moon in the 60s with perfect radio transmission and no delay! They can't even speak from France to UK via satellite without a delay.

[jml]

Hi Marc, thanks again for your reply now I’ve got to try to remember everything I said earlier!.

The issue is that the noise had changed recently and, as I mentioned, it sounds a little like a chattering solenoid. I started my working life as an engineer and I know that changes in noises are one of the things to be concerned about.

I did clean the DPF sometime ago and was pleasantly surprised as to how clean it was and I’ve also been amazed that the car has lasted to 150,000 miles before needing any additive.

The car is an ex- Citroen UK press car (I worked at the Citroen UK HQ for 30 years) however unfortunately all of the people I knew there have now left!.

I just wonder whether, if I were to remove the air doser (item 1 in the pic below) it’s possible to clean it or overhaul it in any way.

I have checked the codes and the only one ( I forget which) was caused by me having disconnected the air doser and I have now cleared this code.

The new noise does trouble me and the fact that the car now has this slight running on sensation also troubles me and I really want to resolve this issue for fear of any further deterioration.

Any help thoughts or advice would be gratefully received.

[jml]

Just in case anybody else is searching this Forum in the future for a similar problem, the problem was indeed the air doser and it turns out that I’m not the only person to encounter this problem on the twin sequential turbo 173 hp 2.2 HDi.

A drive gear inside the unit had worn its teeth away and there is no alternative other than to replace the complete unit. Fortunately they are available from £100 and it’s not too difficult to replace the unit, although access isn’t brilliant.

This is what the outside and inside of the failed unit is like, with a drive gear removed to show the most worn part.

[Ceenine]

all for a 20 pence plastic part

[GiveMeABreak]

Sadly it's the way things are nowadays - cheap parts to shave a few grammes off the weight and not designed to last.

I saw a critique of BMWs that highlighted the same thing all plastic engine parts but they have kept prices high whilst quality has gone down big time. And whilst on that subject - Volvo has been in the news with 507,000 vehicles recalled because of fire hazard using plastic in the engine intake manifold. I mean you don't have to be a genius to work that one out. I mean there are a few others using that too - so just looking out for the recall notice......

[myglaren]

Volvo have come in for very heavy criticism for their treatment of workers in their Torslanda factory, sounds quite bad if the news sites are to be believed. This since Geely bought them.
Maybe there is a connection.

All rather sad.

[GiveMeABreak]

Volvo used to be good cars - my uncle swore by them - he had a big 244 / 245 Volvo Estate when cars were made out of metal and it was solid inside and out. I knew a rep that had one of the new D series Volvo's for a company car and had to return it as it was one of those where the engine was some ally alloy and melted - sounds like the Triumph Stag IIRC.

[myglaren]

I had a 265 GLE. it was like a tank. We always had them as company vehicles when I was in Sweden - the boss was connected with Per Gyllenhammar, the Volvo boss at the time - huge discounts

My son had a V60 auto that he was going to give to me when he emigrated to the USA but he never did either, the Volvo pretty much fell to pieces on him - it was only four years old.

I have been considering a V60 as my C5 looks terminal. Maybe not then