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Good morning everyone. Having been a long term user of the very useful 406 Coupe forum I've just joined myself up on here for access to even more support and advice.

Recently I've had some HDI problems that have been discussed on the coupe forum in detail. I've got a 406 Coupe 2.2 HDI without fap and egr and remapped. In summary I got an anti pollution fault and the car went into limp mode. PP2000 stated "Permanent fault turbo pressure measured too low".

I have replaced the turbo electro valve and that has taken the car out of limp mode, however I now have a weird noise under load. Like a swooshing and whistling like something is sucking/blowing air. On idle this noise sounds rattly under the bonnet. Strangely when I blank the air filter bung on the bottom of the turbo ev this noise stops (as does the swooshing under load). Video of the noise on idle 2.2 HDi turbo vacuum solenoid - noise: https://youtu.be/Za3c6VCJJ1U

Any ideas where this noise could be coming from and any reason why it stops when I blank this off?

Incidentally if I remove the vacuum hose to the turbo actuator this has no effect on the noise so I don't think its coming from the turbo.

Also I've got a faint smell of exhaust gases at the back of the engine around the manifold/egr blanking plate. I can't feel any leaks though.

Thanks for your help

I would thing the first thing to check would be the hoses from the turbo to intercooler and intercooler to engine, if they are OK check that the intercooler itself doesn't have a hole in it.

Peter

+1 definitely sounds like a boost leak somewhere. I think the most common problem on Coupes is the intercooler to air doser hose, IIRC.

Have you still got the bypass heat exchanger, or do you have Nico pipes fitted?

Got the nico pipes. They all seem ok though, no splits or leaks obvious. Wouldn't hurt to have them off and have a look. How will I know if the intercooler has a hole in it?

Rev the engine to give it some pressure, if you cant hear it, disconnect the air intake pipe to the manifold, block the end and try again.

Well the good news is I've found the source of the noise.... The bad news is its coming from the turbo vanes at the plastic inlet side

With the plastic 'python' tube removed I managed to get hold of the vanes to see if there was any play in it. Unfortunately there was quite a bit of play and in moving side to side I was almost able to replicate the weird rattling I was getting on idle.

Video: Turbo vane play/rattle: https://youtu.be/DM4HIUn_bu8

I fear this is the end of the turbo and I'm already pricing up getting it replaced at a garage. At least I know what the noise is now but it spells bad news for my bank balance.

When the engine starts up you can hear the turbo spool up and the rattling begins.

Prior to discovering this I'd had the whole cat/fap and exhaust off to check for leaks. Found this on the cat flexi....

I then hollowed the cat out and blocked one end of it and filled with water to test for leaks but there weren't any. I guess the metal is in order behind the frayed braided section. I am still getting an exhaust smell tho, could that be anything to do with the turbo issue?

There are turbos on eBay for around £150 ( I've been looking too - worst case scenario etc ) so you can get it reconditioned before fitting it to your motor, then flog your old one to get some funds back...

I've been advised to find one on a manifold as its easier to fit..??

http://www.ebay.co.uk/itm/271304696794? ... EBIDX%3AIT

Its from a 607 but I think they are the same...

Managed to source a reconditioned turbo that's done 17k on another members car. Gonna go down this route as its a good price.

I can get my old turbo either reconditioned or sold on to recover some of the costs

Cool, I hope it sorts out your problem (s)...

So do I if I'm going to the trouble of getting the job done.

I'm also wondering where the exhaust smell is coming from tho, this is really puzzling me. Is the manifold prone to leaks?

Questions...

1) is the exhaust manifold prone to leaks on the HDi? I notice you can get a gasket on service box and wondered if I should have this changed whilst the work on the turbo is being done.

2) does anyone know the part number for the gasket between turbo and manifold? I've found this but its in Europe and will take too long to get to me http://pages.ebay.com/link/?nav=item.vi ... 65&alt=web

3) I'd also like to replace the cat at some point as the braided section has frayed. Can you buy a stainless decat pipe anywhere? Something that still resembles a cat perhaps? Ideally I'd like to do away with the cat and fap in place of one single stainless pipe but I believe this would be an MOT fail, regardless of emissions/particles tests

Remapped 2.2 in Turbo nom nom nom shocker?

Welly wrote:Remapped 2.2 in Turbo nom nom nom shocker?

That helps, thanks.

The turbo can withstand up to 1.5 bar pressure and my map is at just over 1.3 bar. I've not thrashed it and the car has only been remapped for about 12 months. I don't know what's caused this but I can't do anything about it now. Hundreds of other hdi's are remapped without turbo issues. In fact it's quite a rareity for these things to go. But again, thanks for your useful input

Sorry I wasn't being critical, we've never ever seen turbo problems with the HDi's and I wonder if the 2.2's slightly more complex VV Turbo might start to break down under higher boost, especially as most of these units are 12+ years old now, it was just a thought.

I hope you get yours sorted ok.

Yeah fair point. I think the most crucial thing with turbo longevity is regular oil changes and letting the car idle for 30 seconds before shut off. I've always done this during my ownership, unfortunately I cannot be certain previous owners treated it with the same care.