P0401 EGR insufficient flow-vw passat BKP

[DieselMonster]

Hi everyone, so I have the fault mentioned in the title and it's a pretty widely discussed issue. To talk you through a bit of the cars history, the original engine had coolant loss, no visual signs, I dumped twice at different times coolant loss sealant. Once engine was changed the coolant loss continued, so that told me it wasn't a leaky head, the engine didn't smoke either. Second engine came at 191K and coolant loss continued at a very small rate, I'm talking the coolant overflow tank would reach minimum lvl once a month, second engine also had white smoke unlike first, not too excessive. Then the turbo actuator was replaced, it was calibrated by comparing the other actuator (I know, wrong way of calibrating it, you should use a muty-vac). So then the emissions garage sign would come up, no lights on dashboard or limp mode. I thought damn, actuator isn't happy with its settings. I would rev engine and once above 2K reves it would make this whining noise, I thought it was turbo overspolling (but I thought, why no limp mode then?). This was the noise for anyone interested

VW Passat B6 3C 103kw BMP EGR Cooler squealing - YouTube (https://m.youtube.com/watch?v=tqAUYu5Tw5A)

Long story short I hooked up the computer, got the code, read a few threads and I believe the whining, emissions garage, missing coolant is all due to the egr cooler. When engine was changed 10K miles make, egr was well cleaned and I do drive my cars hard. Now my question is, I know the egr cooler is whining, it maybe the reason of potential coolant loss and egr throwing up a code. The only question I have is perhaps I had a leaky radiator too, that's why coolant was at a higher rate. Also does coolant seal even go through ear cooler passage? So what is the conclusion, is it fair to assume that the damaged egr cooler that enjoys whining is also leaking coolant hence white smoke from exhaust and emissions light. Perhaps the reason why previous engine didn't smoke or make a whining noise is cos I had coolant loss else where. Also if I haven't mentioned, this whining and emissions light occurred once I got the new engine. Perhaps they didn't put it together properly, hmm....

[niall campbell]

first thing I would do is replace the cap for the expansion bottle . Its cheap and a good starting point, buy brand new and you can waste a lot of time looking for a leak that isnt there

[niall campbell]

2nd thing is watch this on youtube Symptoms of a bad EGR cooler - YouTube (https://www.youtube.com/watch?v=e-LnwSF3ktc) near your video


you need to badly replace that egr cooler , that's a terrible noise

[DieselMonster]

I have changed it and the fact that it was leaking more prior to using stop leak fluid suggests that it isn't leaking from the cap. I read this really good article which I can't darn find which suggests that when a egr cooler goes bad coolant either leaks at exhaust or makes its way into inlet. Worst case scenario is the coolant turns into steam, enters combustion chamber and due to the steam, causes a higher pressure combustion leading to head gasket failure. Coolant going from egr cooler into the wrong place can also cause hydrolock too which is another awful outcome.

I have read that when coolant goes where it shouldn't, when starting her up cold, she runs really rough with white smoke coming out. I'd like to add this to what I have already mentioned, upon cold start-up the engine is rough, revs jump up and down between 800/1000rpm for less than 5 secs. If I start her up again after running her for 5 mins even with engine still cold, she fires up straight away. What is causing her to run rough the first time? I believe that the guru that mentioned egr cooler failing and causing coolant to go where it shouldn't is the answer. I've been driving like this for 10K miles, thinking I just had a unhappy turbo, silly me. I never even knew egr cooler failure was so disastrous. I'd like to also mention it has had recent filters changed, correct oil put in for the pd engine, 5W 40 pd engine oil. I believe with egr cooler hissing, consuming coolant, white smoke, rough early morning starts and computer throwing a fault code, it is fair to assume that this is the culprit. My previous engine on cold start fired up cold nicely, this engine doesn't, I thought there must have been something in this engine (not components around it) that caused rough start up, but I was wrong. It was due to a degraded egr cooler. Inspecting the egr cooler so see if it's had coolant, it should be wet and the eye valve. I will have a pressure test done to see where the leak is, but even if egr cooler isn't drinking coolant, we know it's knackered from the other symptoms so it's replacement time for it.

This is the past number for the egr cooler 03G131513J. I can only find used ones and don't have a clue where to find the gaskets for it. Luckily the egr cooler second hand is very cheap. I'd also like to ask do you guys feel that the when changing egr cooler that the oil cooler should be changed at same time. I have heard they should be. With everything brought to light, is there anything you guys could add, I'd like to know what you guys think, if I do replace egr cooler I'll be flushing the system, is ionised water the best to mix with the coolant to fight rust?

[DMitch16]

Nothing to do with the EGR cooler. If I was a betting man (and I can hear your DMF plates rattling) I'd put money on either the excess movement causing the flywheel to catch the thin metal ring gasket between your gearbox and engine or you have a dry release bearing and the ball bearing are making the noise as the speed and heat increases. The screech is metal on metal and there are no parts in the EGR cooler that will make this noise. If you decide to renew your DMF I am sure you will see evidence of scraping or a failed release bearing.

[DieselMonster]

I've heard in my time two different DMF's on their way out, they make a rattling noise, no such noise is made from my car and if it was, I know it would be DMF. You can also find out that it is DMF by pushing clutch in, sound should disappear. My noise is a hissing noise, no rattle, I do have slight dmf noise tbh and when I push clutch in it goes, I have distinguished the two different sounds. The hissing noise kicks in at 2000rpm like a loud whine, if it was turbo it would throw a code and put me in limp. The noise is exact same as the above video. Perhaps when the thin metal gasket is worn it does make that sound too. Hmm....only DMF noise I've heard is the worn springs between the two plates smacking each other causing a clatter sound. So with this all in mind, you still think it's the DMF? What about coolant loss, white smoke, the code the computer throws up, rough start, this is all just a coincidence that all the things that suggest egr cooler is shot occurs. I'm not saying I know better than you, I'm not trying to undermine you, but it does beg the question.

[DMitch16]

I was only answering the noise on the video link but now realise it was a sample from another car - which had a failing DMF (100% sure of that as identical to mine before I changed it). As for the coolant loss have you checked the top of the gearbox for signs of coolant pooling in the mouldings. If the gasket goes on the connector below the tandem pump it can pool coolant on top of the gearbox a lot of which will evaporate. Other causes of loss as you know are internal corrosion of the EGR cooler tubes or head cracks (present on over 50% of these engines but most small enough to be within VW normal operating tolerances). Most larger head cracks allowing coolant into the cylinders will blow the first EGT sensor most of the time as the sensors don't like getting wet.

Do you get white smoke when the car is running at normal engine temperature (this eliminates normal start up condensation evaporating when the car is still cold and the exhaust warming up)?

Is there any moisture under the carpet in the footwells (bad matrix)?

Have you left the undertray off overnight with a piece of dry cardboard underneath across the entire engine? Easy way to find external leaks. Finally the bottom corner of the radiators where the plastic side tanks fit are prone to corroding and leakage as is corrosion / damage to the top channels (you may see a pink crusty line down one side of the radiator.

[DieselMonster]

Okay I understand, I haven't checked under the tandem pump or left a piece of cardboard under the car. I have checked under the car with it running at operating temp on a lift. Idling and reving at 3000rpm and no drip onto floor.

No I do not get white smoke at operating temp, I only get that combined with a rough start up with revs going up and down at a first start up of the day. The engine will not run rough when starting up cold unless it's been left for a number of hours. I have been driving for 10K miles and without fail the rough start up occurs on first start up of the day or a few hours of it sitting. The white smoke isn't huge, it also doesn't have a nasty smell. It's just a little smoke for a few mins that could well be evaporating, I guess to find out why the revs jump up and down at first start up it's time to hook up the VCDS and look at the values. But as mentioned, those that have suffered egr cooler issues have had either white smoke and rough start up or both combined.

Their is no moisture on the carpet, haven't checked under the carpet though but I doubt it would be, will check though! I will also check the edges of the radiator but I have had quick checks before and haven't seen nothing. I have generally scanned top and underneath of engine, haven't seen any crust. I guess I need to do a pressure test to see if it's internal or external leak. I doubt it's a cracked head as it had coolant loss before the second engine, unless bad luck gave me two cracked heads. There is online info to find out if head I have is prone to crack, will check. But I think it's 05/early 06 which are mostly affected. Mines a 56 car but I don't know when new engine was manufactured. I think BKP went up to 07.

So I will check footwell, radiator, have a pressure test done if still no find and try to find someone with a VCDS, I think most specialist VW garages should have them. I need to speak to VW/diesel garage experts and see their consultation. I also should check egr to see if it's wet or been steam cleaned.

[philipharmes]

I don't know if this is practical but could you not isolate the coolant pipes from the EGR cooler.
Then no possibility of coolant leaking via the EGR or getting into the engine through this route.

[DMitch16]

BKP I believe goes to early 2009 - they made slight changes in 2007 like glow plug relay voltage 7v to 4.4v but bad cracks affected engines into 2007 for sure as my March 2007 BMR had a head change in 2012 to a much stronger AMC head. I know of two 57 plate engines having cracks, one BKP and the other a BMR like mine. It is possible that coolant is seeping into the cylinders when cold as cracks are bigger at that point and seal temporarily as heat expands the head metal at normal temp. Makes the first start harder. Mine ran really well even with a cracked head though but after a while I could not go on as it was blowing the EGT sensors one after the other (£125 a pop and she blew 4 of them! Fortunately VW covered the first 2 under parts warranty). Oil coolers can leak water into the oil but you'd get some 'mayo' in the oil filler cap if this was the case.

[niall campbell]

Ok so the cap has been changed, you put in Stop Leak & its worked a bit. I hate the stuff

The video has nothing to do with your car & I could only go by the other person stating it was coming from EGR without hearing it myself

The white smoke on start up, is this when its cold frosty weather or all the time ? I would expect white smoke in cold weather, yet in warmer weather, this to me indicates unburnt diesel, possibly glow plugs not working ...................... or start of head gasket, cracked cylinder liner with the coolant loss etc

[Daniel71]

try to do a coolant pressure test and also, how someone wrote above, you can bypass the egr cooler to see if the engine get the same white smog

[DieselMonster]

Okay so I checked a few things right now, I first of all looked at the cylinder head revision number and the good news is it's 03G 103 308 C this means that it's the best revision of the cylinder head with A being the worst and B improved. This doesn't mean my head isn't cracked, it just means naturally I don't have the head that's prone to crack. I checked the radiator, a bit of wetness, wasn't coolant, there where a few coolant lines that were a bit wet, could be tiny leak or nothing. There was oily residue around the CCV valve and I don't know why it's there, gave it a good clean and will hopefully see if it comes again. The pipe that attaches too it doesn't seem to fit properly, it wasn't loose but looking at the pic it doesn't cover all the CCV pipe. I also attached a video of my car, when I start her up cold she makes this noise, it sounds like a squeaking belt or water pump but it doesn't make this noise once warm. Can anyone identify what this noise is?

As for the white smoke, it's not always there, tbh it rarely is I think, I think it mainly does it when it's cold so we will write off the white smoke as just vapor for now. I saw the EGR cooler, now I know where it's located, I couldn't examine it as inlet pipe was in the way. Do you guys think if I was to check the EGR cooler or valve for wetness, which would be easier for analysis? I looked at the tandem pump but I couldn't see much again cos of the inlet pipe. But I didn't see anything suspicious. I guess the car needs a pressure test, I'm actually thinking of making one of my own. Get a air compressor, gauge and a pipe with a hole in a spare coolant tank lid. Amazon sell for £50+ for anything decent and garages would charge similar price.

VW Passat b6 unfamiliar noise - YouTube (https://m.youtube.com/watch?v=4YN1vpl3gsA) video of weird noise.

3436334364

[DMitch16]

Easy one - noise is dry roller bearing somewhere: Alternator pulley, AC compressor pulley or belt tensioner pulley. Loud enough to rule out timing system tensioner rollers which would be more muffled due to plastic covers. Tensioner also 'flicks' a little which does not happen when all roller bearings are smooth suggesting resistance in a roller bearing in the circuit.

Also test your vacuum lines to the valve on the EGR cooler as there is a flap that opens and closes to control the amount of EGR gas cooling through the cooler tubes inside. There are narrow tubes and one larger diameter tube. The flap allows different levels of cooling by closing off some of the tubes.

[DieselMonster]

Okay that's great, glad it's not too serious. So I've gone on internet and collected pictures of the EGR cooler and it's actuator flap. Now before talking about the flap, there are six pipes that connect to the EGR cooler. One is on the far right, two on the left with one of them having a metal pipe attached to it. I take it these are the gas pipes or are they coolant, they look a bit too big in diameter for coolant. Then there is the actuator, does this hold vacuum like a turbo actuator does or does it just open/close flap? Next to the actuator are four small pipes with two of them being attached onto the actuator block as you'll see on the images where the actuator is disconnected from the rest of the egr cooler. How do I test the vacuum lines, first I'll need to identify which ones are the vacuum lines before I test them.

[DMitch16]

Two small metal pipes are additional coolant hose connectors. The vacuum pipe connects to the top of the actuator.

Google 'VW SSP 316' for a PDF of how the 103kw engine works - there's some quite useful info in there.

[DieselMonster]

It sure is an interesting read, I'll read through it all tomorrow. It's a good reference guide, there are a few of these PDF's floating online. So I got creative and realised that there wasn't much info on BKP engines with the BKD getting all the attention I googled that and found an absolute awesome guide on how to remove egr cooler. I'll be gathering all what I need as its my first major engine component removal. I'll be sure to keep you all informed of what happens.

How To: EGR Valve / EGR Cooler Delete Mk5 TDI (BKD / BMN) - page 1 - How to Guides / Troubleshooting - MK5 Golf GTI (http://www.mk5golfgti.co.uk/forum/index.php/topic,72241.0.html?PHPSESSID=33kbq09o8qeaimdoler5t hqee5)

[DieselMonster]

Okay so today I removed to egr cooler, it only took 8 hours! I haven't even fitted the replacement yet but should be much more straight forward as I know what to do. My main issues was bolts from turbo exhaust manifold to egr cooler and dealing with the coolant. Must have lost 1 litre of coolant. So upon removing the egr cooler, the actuator was sticking (the flap) there wasn't any coolant found within or around it. Instead after removing the intake pipes, I found a small puddle of coolant near the tandem pump. There wasn't any on gearbox if I recall. Additionally, one coolant hose that goes to the heater core which connects near tandem pump was badly damaged. I have an image below of the coolant near the tandem pump. Sadly there is no signs of it coming directly from tandem pump. So I still don't know where it's leaking from but I have definitely rounded it off the that area. Does the image provide enough evidence tandem pump is leaking? If so I wish to deal with it while everything around it has been removed. 3491734918

[DMitch16]

In the 2nd picture is a plastic union that connects the big hole in the head with that side of the cooling system. The gasket in between is subject to perishing and leaking coolant out on top of the gearbox. The pipe union also has the second coolant temperature sensor inside (you can just see it to the right and at the bottom of the plastic union). If you have the coolant out it is an easy removal with just the 2 bolts either end of the union. Gasket is a few quid from VW and it is important to clean the side of the head before refitting as the seal is very good providing it is against a smooth, dry and clean surface with proper torque of the 2 bolts.

34920

34921

34922

[DieselMonster]

That's exactly what I have been looking to do since further inspection. I thought it was tandem pump as you mentioned before but then I looked closer and saw the coolant flange to be leaking. Either due to worn out O ring or the plastic itself becomes brittle over time and has an hair line crack. I will be getting all three new O rings and a coolant flange as the plastic can become ruined. I haven't taken all the coolant out, hopefully once I remove the flange via the two screws there isn't too much coolant that comes pouring out of the head. I have reinstalled the new egr cooler, only took a few mins once you've wiggled it past the cylinder head. There aren't any torque specs for the egr cooler and I can't get new gaskets but I will ask VW. Do you know of the torque specs for the coolant flange to cylinder head? I'll check the Haynes manual in the mean time.

[DMitch16]

Something like 15Nm for the flange iirc but best to check as overtightening will crush the rubber o ring gasket. The flange is less than £15 from the dealer and comes with an o ring gasket. Give the coolant temperature sensor a quick clean before you refit.

[DieselMonster]

They say about 10nm to 15nm from various sources. I have ordered a aftermarket coolant flange, it should be good enough. Aftermarket one was £16, VW was asking for £32. I've also ordered the second O ring for the temp sensor. Will MAF cleaner be fine for the sensor when cleaning it?

[DMitch16]

They say about 10nm to 15nm from various sources. I have ordered a aftermarket coolant flange, it should be good enough. Aftermarket one was £16, VW was asking for £32. I've also ordered the second O ring for the temp sensor. Will MAF cleaner be fine for the sensor when cleaning it?

Wow that's gone up - changed mine 4 or 5 years ago after a garage stuck it back on with silicone sealant to a new head they fitted (old one was cracked)!! Started leaking a whole tank of coolant in 20 miles. Wipe it clean with what ever you have as only surface deposits may affect its capability (the real magic happens inside so as long as it is not caked in limescale or rust it will be fine - unless faulty in which case might be worth it to pop a new one in while the pipe is off).

[DieselMonster]

So I put everything back together and vcds is still showing egr insufficient flow. I went onto the engine control on vcds and clicked on egr to see the flow. The flow remained the same even though I reved it 2k. Check last two vcds pics below

VW Passat B6 (https://www.dropbox.com/sh/7pm73j2q2bm6y9o/AAAHJ4g6OA3hC0VHFLZA8PMNa?dl=0)

Is the valve stuck closed?

[Gazwould]

Blank and remap .

[DieselMonster]

An option but I thought cooler engine temp was good for the engine.

[Gazwould]

Dervs don't run hot , it's a case of do you want oxygen or less oxygen , less oxygen = incomplete combustion = soot .

[philipharmes]

So I put everything back together and vcds is still showing egr insufficient flow. I went onto the engine control on vcds and clicked on egr to see the flow. The flow remained the same even though I reved it 2k. Check last two vcds pics below

VW Passat B6 (https://www.dropbox.com/sh/7pm73j2q2bm6y9o/AAAHJ4g6OA3hC0VHFLZA8PMNa?dl=0)

Is the valve stuck closed?

Did you drive the car or was it stationary.

The EGR only opens at partial throttle & may not open at all ( part of the defeat software I would have thought ) while the car is stationary.

So the way it operates will also depend if youv'e had the software update or not.

[DieselMonster]

It was stationary

[DMitch16]

Blank and remap .

Which never gets any less against the law the more you say it :aargh4:

[DMitch16]

Dervs don't run hot , it's a case of do you want oxygen or less oxygen , less oxygen = incomplete combustion = soot .

Higher temp combustion = more Nitrogen Oxides = add more lung harming pollution to the air = more children with breathing issues and lung diseases. A blanked EGR does increase the cylinder combustion temperature, period. DERVs although lower revs generally run hotter than petrol but that is not the issue. Blanking an EGR is enough to increase combustion temperature to a point where Nox emitted is 5 fold what it was before.

[Gazwould]

Got a link to the 5 fold effect ?

Every boiler flue pumps out NOx but the motorist is an easy government tax victim .

How do they accredit individual ailments to NOx ?

With a blanked egr thus more complete combustion you get more low down torque , more mpg , cleaner engine oil , higher NOx but less diesel particulates .

[DMitch16]

With a blanked egr thus more complete combustion you get more low down torque , more mpg , cleaner engine oil , higher NOx but less diesel particulates .

This part is true but nitrogen oxides is the invisible killer. I don't dispute the better performance but having personally been subjected to excess nitrogen oxides which caused unruly heart arythmia (my medical history confirms the cause) that disappeared when no longer subjected to it, I am a walking, living, thank goodness, test subject. There are countless scientific examples and tests online regarding diesel combustion temperature and levels of NOx emitted. Once over a certain combustion temperature of around 1300° all show exponential increases in NOx gases (I used 5 fold but some much higher).

Red diesel is far cheaper than regular diesel and our cars can run perfectly well on it so why don't we recommend everyone to get red diesel? Because it is also illegal, misuse heavily fined and a result of the Government wanting motorists to pay huge amounts of tax on refined pump diesel yet the suggestion for someone to remove an emissions controlling item is OK?

Perhaps once emissions control parts removal is heavily fined and difficult for people to get away with such changes, it will no longer be suggested.

[Gazwould]

What cause was your particular over exposure to NOx ?

[DMitch16]

What cause was your particular over exposure to NOx ?

Turbo to DPF gasket leaking on a borrowed Golf GTD which unbeknown to me had the DPF gutted and blanked EGR the year before which made things worse than it would have been. Had it for 3 weeks driving 2 hours daily with cabin slowly filling with exhaust gases. Heart started to palpitate erratically and as I couldn't find any leak at the time and because my worsening condition only started when I began using the car, my partners father, an Environmental Technician took the car and tested the interior air quality. He found a number of toxic gases coming into the cabin but a proportionally higher Nitric Oxide content when the car was running. He eventually found the small leak from the gasket with the exhaust gases being sucked in through a bulkhead hole straight into the blower. I stopped using the car and the palpitations subsided. My doctor said that the palpitations would almost certainly have been as a result of Nitrogen Dioxide or Nitric Oxide gases (which was heavily present) due to the type of arythmia I was experiencing. If Carbon Monoxide had been higher it would have probably left me with long term heart muscle damage too which is not evident. I count myself lucky.

[Gazwould]

Could said Environmental Technician test the effectiveness of a Mann Hummel Ferocious Plus Activated Charcoal pollen filter Vs ordinary pollen filter on the presence of NOx ?


https://youtu.be/IIxaEDcTtYU

Numerous studies , TV programmes all conclude that car occupants are most at risk compared to bus passenger , pedestrian and cyclist because the small cabin builds up with concentrated levels of pollutants coming in through the air vents .

[DMitch16]

Could said Environmental Technician test the effectiveness of a Mann Hummel Ferocious Plus Activated Charcoal pollen filter Vs ordinary pollen filter on the presence of NOx ?


https://youtu.be/IIxaEDcTtYU

Numerous studies , TV programmes all conclude that car occupants are most at risk compared to bus passenger , pedestrian and cyclist because the small cabin builds up with concentrated levels of pollutants coming in through the air vents .

Said Technician did discover a plain pollen filter and recommended that the owner change this for an activated charcoal one once the car was given back and the turbo gasket leak was rectified. I always fit a Mann activated charcoal version in every car I own or have previously owned.

Aside from harmful invisible NOx gases do you happen to know what one the biggest contributors to airborn particulate levels is?

[Gazwould]

https://upload.wikimedia.org/wikipedia/en/thumb/d/df/Airborne-particulate-size-chart.svg/800px-Airborne-particulate-size-chart.svg.png

[DMitch16]

Interestingly this does not mention tyre or brake particulates that make up 11% of all smaller than 2.5PM sized contaminants which follows (on particulates emitted by a car) exhausts at 18%. In fact brake dust particulates are presently higher from electric and hybrid petrol electric cars than they are from standard combustion engined only vehicles. Another part of motoring that will be targeted soon.

[Gazwould]

I did post elsewhere an article someone wasn't happy enough about particulates as tyre and brake pads contribute .

Nothing good about dusty oem & OE pads thats why I have low dust Redstuff front and rear .