EGR should we all be more concerned

[neil]

Does anyone know when the EGR was introduced to the VW engine.

Have had a few people say to me I should be doing something about blocking
it off to reduce damage to the motor. Had a mechanic say:
"Most modern diesels with EGR will get through the warranty period (just) before failing due to EGR. "

Does anyone have a high mileage vehicle which has the EGR.

Been some good threads re: the EGR and would seem 3 options. Block it off,
Vag com to increase air supply or the provent option.

So any chance some of our more experienced guys can give us their views
on this issue. Should we all be more concerned with these newer diesels especially regarding the EGR.

Thanks guys
Neil.

[Greg Roles]

I'm unsure if EGR leads to "failing", but it certainly leads to a gunked up inlet and manifold. You'll notice on TDi club all the US guys use Vag com to drop their EGR down to virtually nil, but as yet to my knowledge no-one has really sorted that out on the MKV. I certainly tried simply unplugging the EGR valve, but after testing it, and it driving poorly and throwing an error code which I had to use Vag Com to clear, I worked out that it defaults to wide open with no cooler. Unplugging it just increases the EGR amount, and it isn't cooled, which obviously is bad!

The "throttle flap" works in conjunction with the EGR to actually block off the inlet and create a vaccuum to draw EG into the inlet, and I am of the understanding that it will just keep trying to add EG to the charge if it's physically blocked off, and actually choke the car somewhat. I think the car can actually sense the amount of EG added to it, and that blocking it off messes up a few systems, so we need an electronic solution as well.

Don't forget the WHOLE idea of adding EG to the charge is to actually reduce the combustion temps and thus produce less NO. Blocking it off will potentially increase your EGT's, and what I measured, in my GT at least was a pretty scary stock 820 degrees. The yanks suggest lower than that for turbo longevity in their behemoth SUV diesels, and only Shadowmaker thus far has suggested about 900 is a safe limit he has seen. It's certainly a thing to consider!

Even with a provent, which you can read about on page 2 of my tinker thread, my throttle flap and EG valve area was caked black at 30k, so you guys without are going to have a lot more gunk in there. I could stick my finger in, and pull out thick black oily sludge, like out of the bottom of an old sump. It surprised me!

The EGR circuit actually aids warmup, which is a good thing, so any blocking should leave the hot circuit open, which closes off at about 30 degrees water temp. Certainly what I'd leave operational.

So to my understanding, we're kinda stuck with it for now, at least until some aftermarket solutions happen. A Provent is a good idea all the same, expensive as it is.

[peedman]

Yeh i agree, the egr gunks up the intake alot and the only way to remove the black build up is to take the intake off itself and clean it. It is literally a few mm thick and would be good if i coulda cleaned it. I removed the egr from my mk3 diesel and it had lived 150k with it on so i wouldnt believe that egr's cause things to fail. That said my car is very different to the newer tdi's.

[gregozedobe]

I read somewhere that the EGR is supposed to be less troublesome on newer TDIs than the old TDI engines, plus the lower sulphur diesel we get these days also reduces the problems some.

There was some discussion that the EGR operates for a greater percentage of the time when you aare driving in stop-start traffic, and is not running when you use full accelerator.

I didn't find much that sounded like the author really knew what they were talking about (ie reliable, factual info) for the most recent VW TDI engines, but I only googled for an hour or so, so there may still be some gems of info out there that I didn't get to read.

[Buller_Scott]

cogdoc,

are you particular about which vendor you fill up at? or does the LSD vs. ULSD difference not really account for jack all?

Also, after how many kms did you install your provent? (im reading that you installed your provent AT 800k, and even then, at 30k, yet there was STILL alot of gunk in there?).

Apparently the disabling the EGR also forfeits one of the runaway safety functions of the engine- dont ask me to explain as im not mechanically minded, but even i know that i wouldnt be particularly keen on forfeiting THAT, whatever it is.

In terms of turbo inlet- did you clean yours out? or just put prOventative (<-awesome!) measures in place with a plan to improve upon that once more options become available?

in terms of EGR, is it just the turbo that suffers as a result of oil sludge in the manifold? or are there rather negative implications for the longevity of the engine itself? i dont give a rats about replacing a turbo every 100,000kms, but it would be a real shame to think that my little oiler, which i bought specifically for longevity, would be outlasted by its petrol brother and thus rendering the $6000 price difference a complete write-off.......

[Greg Roles]

Hey Scotty,

My car lives on BP, and BP ultimate since it was released. At best it's had two tanks from other places. My provent went in at the 800K mentioned, but that means it's had 29200kms of MUCH less oil blowby into the inlet prior to the turbo, and still it had an alarming amount of black gunk in there. The Provent removes a lot of oil, but obviously even then some still gets ingested.
I plan on removing the hot side of the EGR, but only at a point I can get a custom tune that still allows the car to run as pollution free as possible. I have other ideas on lowering combustion temps.

The run away prevention is the throttle flap mechanism, a seperate mechanism below the EGR pipe, it shuts off the inlet on shutdown, and if there was a case of runaway, turning the car off would save it. I've also unplugged that, and it is noticably harsher on shutdown, has a bit of over run. I'd be leaving that in, but again, I'd like to tune it so it just does the start stop function.

The sludge starts where the egr pipe enter just prior to the black plastis inlet manifold, and it's a good bet the entire plastic manifold is similarily coated in sludge.

All just ideas at this stage though!

[mikinoz]

Has or can anyone do a DIY on cleaning the throttle? I had this noted on my 30K service, but thought at the time another sting on top of the already overpriced service was not needed...

Love to hear if anyone has done this themselves...

[Transporter]

Hey Scotty,

My car lives on BP, and BP ultimate since it was released. At best it's had two tanks from other places. My provent went in at the 800K mentioned, but that means it's had 29200kms of MUCH less oil blowby into the inlet prior to the turbo, and still it had an alarming amount of black gunk in there. The Provent removes a lot of oil, but obviously even then some still gets injested.
I plan on removing the hot side of the EGR, but only at a point I can get a custom tune that still allows the car to run as pollution free as possible. I have other ideas on lowering combustion temps.

The run away prevention is the throttle flap mechanism, a seperate mechanism below the EGR pipe, it shuts off the inlet on shutdown, and if there was a case of runaway, turning the car off would save it. I've also unplugged that, and it is noticably harsher on shutdown, has a bit of over run. I'd be leaving that in, but again, I'd like to tune it so it just does the start stop function.

The sludge starts where the egr pipe enter just prior to the black plastis inlet manifold, and it's a good bet the entire plastic manifold is similarily coated in sludge.

All just ideas at this stage though!

Hi Cogdog,
Has the return hose from Provent to inlet duct any oil in it?
On my T5 the return hose is completely free from the engine oil (the hose is red inside - easy to spot any oil inside it). I plumbed the Provent in the way that I'm catching the oil from the bottom oil return port, rather than returning it back to the sump. Could it be the turbo oil seal? I would also be checking inside the intercooler for the excess oil.
On our Golf at 600km from the new the oil was already dripping from the rocker cover connecting hose. I can imagine how it looks like inside of the intercooler now. I didn't install the Provent in it yet, it's done 17,000km now.

[HiTorque]

Has or can anyone do a DIY on cleaning the throttle? I had this noted on my 30K service, but thought at the time another sting on top of the already overpriced service was not needed...

Love to hear if anyone has done this themselves...

I managed to get into EGR valve and EGR motor flap section and nearly had heart attack when I saw amount of black sht inside. The car was regularly serviced and clocked 65K in 4years. I cleaned it, but motor was damaged already so the car is back to the dealer.. it must have a catch can otherwise this will happen again. The deposits were 3-4 mm thick and some could only be removed with metal brush. I am considering fixing it and getting the magic catch can or sell the car. It took 2 hours to remove all bolts as two of them were completely inaccessible.

[Greg Roles]

My Provent has a lower hose to collect the condensed oil it catches, and it fills with a decent 100mL-200mL amount every 5000km roughly. The return line has oil film in it, and there is obviously still *some* going through the inlet. Basically I've dramatically reduced it, not eliminated it. The T5 is a different engine, so I'd expect different oil blow by. Still, I'm amazed you have absolutely no oil film!

Perhaps I could use the now unecessary water intercooler parts I collected to water cool my provent to try and catch more oil!

It's a big concern for the diesel engine for sure.

[Greg Roles]

and just so you know it's not happening because VW is slack, check out the very complex oil seperation in your tappet cover, stock! Hate to think how much would go through without this!

[Greg Roles]

And while we are on the subject, I found the following alarming piece of information hidden away in my 2.0L common rail self study program last week:

"A small amount of engine oil is always burnt while the engine is running. Some of the burnt engine oil collects in the DPF in the form of ash. This ash cannot be decomposed during active regeneration.
To ensure efficient functioning of the DPF, the limit value for the ash mass needs to be checked during service. The DPF should be replaced when this limit value is exceeded."

Basically, once you burn enough oil to "fill" the DPF with ash, you're up for a new one. Lucky a honeycomb of ceramic Silicon Carbide, coated with aluminium oxide, cerium oxide and Platinum comes cheap....

If you aren't considering a Provent for the sludge issue, do it for the longevity of your no doubt expensive DPF lifespan! Oh and use LOW ash oils in DPF cars!!!!

[HiTorque]

And while we are on the subject, I found the following alarming piece of information hidden away in my 2.0L common rail self study program last week:

"A small amount of engine oil is always burnt while the engine is running. Some of the burnt engine oil collects in the DPF in the form of ash. This ash cannot be decomposed during active regeneration.
To ensure efficient functioning of the DPF, the limit value for the ash mass needs to be checked during service. The DPF should be replaced when this limit value is exceeded."

Basically, once you burn enough oil to "fill" the DPF with ash, you're up for a new one. Lucky a honeycomb of ceramic Silicon Carbide, coated with aluminium oxide, cerium oxide and Platinum comes cheap....

If you aren't considering a Provent for the sludge issue, do it for the longevity of your no doubt expensive DPF lifespan! Oh and use LOW ash oils in DPF cars!!!!

I contacted mann-humme people for Provent, they are 200m away from my office, will see if they can offer something.

[Transporter]

My Provent has a lower hose to collect the condensed oil it catches, and it fills with a decent 100mL-200mL amount every 5000km roughly. The return line has oil film in it, and there is obviously still *some* going through the inlet. Basically I've dramatically reduced it, not eliminated it. The T5 is a different engine, so I'd expect different oil blow by. Still, I'm amazed you have absolutely no oil film!

Perhaps I could use the now unecessary water intercooler parts I collected to water cool my provent to try and catch more oil!

It's a big concern for the diesel engine for sure.

The Provent has adjustment on it. Look in the Provents instructions if you didn't try it already; maybe you just need to adjust it a bit. I've had so much oil going through the intercooler hoses on that T5 that the oil was dripping out of the joints where the hoses connect to metal pipes for the intercooler (they use O-rings and the clips instead just clamp over the hose).
I installed the Provent at 3,000km.

[Greg Roles]

Cool, will do. All I noticed was a relief valve, is that the adjustable bit?
I'll fish out the paperwork tonight.