2.0 HDi noisy EGR valve

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StuY
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2.0 HDi noisy EGR valve

Post by StuY » 16 May 2015, 01:22

My recently bought 90hp 2.0 HDi 206 often makes a clinking or pinging noise when the accelerator is pressed or released. I can produce the sound reliably by blipping the accelerator pedal slightly with the car idling. I'm pretty sure its coming from the EGR valve: if I pull the vacuum hose off the EGR at idle it makes the same sound as the valve slams shut, and if I unplug the electrical connector on the solenoid valve that drives the EGR then the noise goes away completely. The car drives fine, no MIL, no smoke, good power. So, not a big deal, but I was wondering firstly if its a sign that the valve is failing, and second is it worth pulling it off to clean it up? I would pull it off just for a look, but its hidden away down the back of the engine and I suspect that it would be a pig of a job...

Is the valve supposed to be damped to control the rate at which it opens and closes, either mechanically or pneumatically? I imagine that a lack of damping could cause it to become noisy if it was slamming shut.

Any advice much appreciated!

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spider
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Re: 2.0 HDi noisy EGR valve

Post by spider » 16 May 2015, 11:16

I'm not sure there is any damping on it as such if there is it will be in the valve itself I guess. I do not think its a variable valve it is either fully open or shut (I could be wrong)

A 'silent' code will be stored if it detects the solenoid has been unplugged (open circuit) but no 'K' light will come on usually for this.

From a personal standpoint I'm half tempted to say leave the electrical connector on (so it think it is OK) and disconnect and plug the vacuum pipe.

Regarding cleaning it, there are some alleged EGR cleaning sprays around although I'm wary of spraying that kind of material into the intake area given diesels will like to run on anything they can squash and burn :D

It may be worth you removing and cleaning it off the car then refitting or perhaps just seeking a replacement ? :) If you wanted to go this route.

PS, Welcome to F.C.F :)

Northern_Mike

Re: 2.0 HDi noisy EGR valve

Post by Northern_Mike » 16 May 2015, 14:15

spider wrote: Regarding cleaning it, there are some alleged EGR cleaning sprays around although I'm wary of spraying that kind of material into the intake area given diesels will like to run on anything they can squash and burn :
I use the Forte EGR / Turbo cleaner spray on the Berlingo once every 12 months or so when it starts to make a noise.

The spray seems to work, as the rough noise it makes (growling at about 2200rpm on overrun or a light throttle) goes away.

All the engine does when you spray the stuff down it is have a mad fit of diesel knock, I'd not worry about it running-on or doing a diesel - overrun at all. Trying te spray stuff is the cheapest and easiet way to start with..

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wheeler
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Re: 2.0 HDi noisy EGR valve

Post by wheeler » 16 May 2015, 19:51

spider wrote:I'm not sure there is any damping on it as such if there is it will be in the valve itself I guess. I do not think its a variable valve it is either fully open or shut (I could be wrong)
The electrovalve that controls the EGR valve uses OCR pulses to open & close it rapidly, the ECU changes the OCR % pulses to vary the amount of opening so it can open anywhere between 0% & 100% open.
spider wrote: From a personal standpoint I'm half tempted to say leave the electrical connector on (so it think it is OK) and disconnect and plug the vacuum pipe.
You took the words right out my mouth.

Northern_Mike

Re: 2.0 HDi noisy EGR valve

Post by Northern_Mike » 16 May 2015, 19:58

Fix the damn thing.

I'm getting really fed up with advice being given that just gives the go-ahead to run with faulty emissions equipment.

It's not ok. Keep your filthy fumes to yourself. If you can't afford to run the car as it is meant to be, get one you can afford...

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Last edited by Northern_Mike on 16 May 2015, 20:14, edited 1 time in total.

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Stickyfinger
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Re: 2.0 HDi noisy EGR valve

Post by Stickyfinger » 16 May 2015, 20:10

Ditto Mike

StuY
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Re: 2.0 HDi noisy EGR valve

Post by StuY » 16 May 2015, 20:11

Absolutely, and I'm not going to put anything through the engine in an attempt to clean it either. I will either leave it alone for now or pull it off and sort it out, whether that's just cleaning it up or replacing it. As far as I know there's not a lot wrong with it apart from a bit of noise. I've just changed the rear axle, rear transverse arms, front springs, front control arms, drop links, track rod ends, a front wheel bearing, and had a 'mare replacing a glow plug (diy broken tip removal, which I will write up at some point), so I'm not in a hurry to mess about with it if it can just keep on tinkling away for another few thousand miles.

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Stickyfinger
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Re: 2.0 HDi noisy EGR valve

Post by Stickyfinger » 16 May 2015, 20:18

Agree with the cleaner, don't trust it myself but many do and like Mike swear by it.

I would say take it off and give it a good clean is the way to go

Northern_Mike

Re: 2.0 HDi noisy EGR valve

Post by Northern_Mike » 16 May 2015, 20:36

Forte's stuff (Turbo cleaner) is well received by the VAG owners of older cars with VNT turbos on them. The vanes stick and cause overboost errors. Using this Forte stuff seems to cure that and EGR errors. Of course, I doubt that it is as good as stripping and cleaning it buy it's a lot less ballache if it works.

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StuY
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Re: 2.0 HDi noisy EGR valve

Post by StuY » 16 May 2015, 20:50

Ok, screw clamp for the flexi pipe ordered. I'll pull it some rainy day when I get a chance...

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Gibbo_Wirral
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Re: 2.0 HDi noisy EGR valve

Post by Gibbo_Wirral » 18 May 2015, 13:16

Northern_Mike wrote:Fix the damn thing.

I'm getting really fed up with advice being given that just gives the go-ahead to run with faulty emissions equipment.

It's not ok. Keep your filthy fumes to yourself. If you can't afford to run the car as it is meant to be, get one you can afford...

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If it really was churning out "filthy fumes" then wouldn't it fail the MOT on emissions?

StuY
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Re: 2.0 HDi noisy EGR valve

Post by StuY » 18 May 2015, 13:19

As far as I know, the only MOT emissions test for diesels is particulates (smoke); there is no test for NOx emissions.

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Stickyfinger
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Re: 2.0 HDi noisy EGR valve

Post by Stickyfinger » 18 May 2015, 13:29

Italian "Tune-Up" time :)....take it out (check your oil water)....and give the thing a right good chaving....run it up to max revs a few times after getting it hot.....give it a good thashing for a bit, they love it !
Gibbo_Wirral wrote:
Northern_Mike wrote:Fix the damn thing.

I'm getting really fed up with advice being given that just gives the go-ahead to run with faulty emissions equipment.

It's not ok. Keep your filthy fumes to yourself. If you can't afford to run the car as it is meant to be, get one you can afford...

Sent from my SM-N9005 using Tapatalk
If it really was churning out "filthy fumes" then wouldn't it fail the MOT on emissions?

StuY
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Joined: 15 May 2015, 20:08

Re: 2.0 HDi noisy EGR valve

Post by StuY » 19 May 2015, 17:28

So I pulled it off and had a look; not easy. To get anything approaching sensible access to the left side EGR valve nut, you really need to remove the breather pipe, induction manifold elbow and EGR flexi pipe. The only way I could get a decent grip on that left side nut was to grind flats onto a 10mm short socket and hammer an 11mm spanner onto it. If I had done this first of all, before touching it with a ring spanner, I might have had a chance of getting the nut off. As it was, I ended up having to grind a segment out of the nut with a dremel, then knock the nut off using an 18" screwdriver as a cold chisel so I could do the hammering up by the battery box.

The inlet manifold was pretty well gunged up with tarry sooty crap. I cleaned out the elbow and the bits of the manifold that I could reach, but taking the manifold off is just too much of a hassle. There wasn't enough gunk in there to significantly obstruct the airflow. In contrast, the EGR valve was almost clean - only a light coating of dry soot like you would find in any exhaust component. Same with the flexi pipe. I think the heat and flow in the valve is enough to keep it clear, and the tarry stuff mostly gets deposited once the exhaust gas mixes with incoming air and cools down. I cleaned the valve with mr muscle oven cleaner since I had it off, but I didn't expect it to make any difference, and it hasn't. The valve itself seems fine (moves freely and moving parts came up shiny) and the actuator held vacuum well if I opened the valve manually and held a finger over the hose barb.

My advice: if you have a rattly EGR and no other symptoms, don't worry about it. It looks like the valve is (very) unlikely to fail open mechanically, and if the solenoid valve fails open then you can get home just by disconnecting and plugging the EGR vacuum hose.

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spider
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Re: 2.0 HDi noisy EGR valve

Post by spider » 20 May 2015, 13:33

Northern_Mike wrote:Fix the damn thing.

I'm getting really fed up with advice being given that just gives the go-ahead to run with faulty emissions equipment.

It's not ok. Keep your filthy fumes to yourself. If you can't afford to run the car as it is meant to be, get one you can afford...
An older model would not have said controls so it would 'pollute' just as much as not having EGR. Having said that the mess the EGR can create inside the intake manifold (take a look inside a late XUD or DW8 or TUD5) is astonishing. Although its reducing NOx emissions (see next quote) after a few years you've restricted the inlet a little bit with all the 'sludge' so you are possibly buring more fuel due to the reduced air effect (similar to having a dirty air filter) , YMMV though this is just in my personal opinion. :) , having seen the stuff that can come out of a HDi on a manual 'regen' too I'm sort of 50/50 on a DPF as it may just be 'saving' the pollution to be released later ? , not to mention the nasty chemicals needed for the tank too.

:) :) :) < Extra smilies as this is all just in my opinion and is a friendly reply.
StuY wrote:As far as I know, the only MOT emissions test for diesels is particulates (smoke); there is no test for NOx emissions.
I think its just an EU requirement rather than any MOT related test. This is (as far as I know) why diesel EGR started to make an appearance around 1997 or so.