EGR should we all be more concerned

[tonymaroney]

HiTorque,

Yes, that is the one we have been discussing for a few days...the discussion starts back at page 18...it's worth a read, and I have learnt a lot out of it all. I'm not an expert by any means, but here is some of what I have found out... Using the straight through pipe has a few problems associated with it...the biggies are:
1) An engine light will come on as you will have more oxygen in the exhaust than the ECU is expecting. You would normally need to put a Wayne Angle Block in at the back oxygen sensor to space the sensor out of the exhaust stream a bit. The supplier from that site wrote back to me a while back and confirmed you will get the warning light for both the race and the road versions...probably will be intermittent for the road version....the O2 sensor spacer will reduce/remove this issue if done correctly. It's a little of trial and error because the sensor needs to be further back from the exhaust gas, but not too far. The Wayne angle block (see http://www.42draftdesigns.com/faq.htm about 3/4 the way down) normally sets this distance correctly.
2) The exhaust gas temperature (EGT) will rise, because there is more oxygen in the combustion chamber, rather than recirculated exhaust gas which limits the oxygen (giving lower temps of combustion). This is bad news for the variable vane turbos in our TDI's, and particularly bad for the 103kW versions due to less heat conduction than the 125kW versions. You can get a turbo to fail when it goes excessively over 700-800C for prolonged periods, and some of the 103kW's have been doing that (but maybe not specifically due to the EGR powerpipe as such).
3) Replacing that EGR valve looks simple when you stand there at the front of the car, but there are reports that it is way more difficult than it looks.

Installation of a "ProVent" oil catch can in the line between the crankcase breather and the air intake line will help to lessen the amount of oil in the air intake, which then won't have a chance to combine with the soot from the EGR valve, and thus lessen the gunk buildup. Also, I am investigating the idea of shutting down the EGR via Vagcom software, rather than removing it altogether....but the effects on EG temp are likely to be a problem still.
Hope this helps.
Tony

[Greg Roles]

Just to rain on your parade Tone ol mate, that link to TDI club covers the MKIV version of TDI, and as yet to my understanding no-one has come up with a simple Vag Com answer for the EGR. It'll happen for sure, but I found that site early on as well, got a Vag Com, hooked it up, and it's all different.
Quite bummed at the time!

A wayne angle block would allow you to block / restrict the EGR, but remember too that the exhaust is used to help warm the engine up, as diesels take a lot longer than petrol given the much lower combustion temps. Less of a problem given where we live, but not so good for our southern brothers.

The Provent drains out into a lower hose, which I just bung up and drain every several thou, but no reason you couldn't rig up a container with a tap etc. The bottom small outlet is gravity drain to wherever you wish. I do get a good 100-200mL each drain though. This bottom drain isn't hooked up to my exhaust, rather the outlet from the provent, being the vapours post filter are. The Provent has an inlet, a filtered outlet ( to exhaust ) and a lower drain for what the inner filter removes from the inlet gasses.

[tonymaroney]

My parade has officially been rained out!
Nah, it's all good! And yes those links are all for the Golf IV, and thus I won't be turning down the EGR valve via Vagcom anytime soon.

I have purchased a new ProVent 200 unit from Bob Chalmers at Active Air Spares in Sumner Park. I can highly recommend anyone that wants a Provent in Qld to chat to Bob as he was very responsive to emails and questions, and good to deal with in person too. Real customer service...old school style, and he likes to look after his Qld customers! (I have no affliation etc...just a happy customer).

Now I just have to fit it into the Golf V engine bay...hhmm, it's a bit squeezy in there alright! I better figure it all out before I start drilling holes!

Tony

[Greg Roles]

Page 2 of "let the tinkering begin" shows mine. Getting suitable hose, and fitting it is the nightmare. Remember the crankcase has a LOT of oil vapour pressure and needs to flow well. I pushed oil out my turbo bearings in the very beginning by putting a small chunk of pot scourer inside the stock tappet cover to inlet hose, which is why even though I used smaller, silasticed in hose, I have no bends of joins to drop the overall flow. Oil proof hose to fit over the provent fittings is both huge and expensive. It's a problem!

[tonymaroney]

Has anyone ever measured the crank case pressure on a non Provent system vs a Provent system in one of our VW TDI's? I couldn't find much specific to our cars but only general things like:

In stationary Diesel engines, medium speed, four strokes, the manufacturer specify maximum positive crankcase pressure of 30 mm H2O, this is 0,002942 bar or 0,04267 PSI.

Greg I was discussing the Provent with Bob from Active Air Spares and we pulled it all apart to look at it...(as you know) there is a non-adjustable non-return valve at the exit to it that surely will contribute to pressure, or at least "flow-loss"? I would have thought that a few bends in the line would be nothing compared to that non-return valve (that only opens under pressure)? But I suppose that it is all additive and thus it is ok when there are no bends, but add the bends together with the non-return valve and you have a back pressure problem.
Surely you would need some significant backpressure to push oil out of turbo bearings?
I'm glad you mentioned this BTW. I noticed the comments about not having too many bends etc but didn't quite realise it was that borderline.
Tony

[Greg Roles]

The Provent valve opens at 1psi, so it's only slightly positive pressure. My oil line is only pencil sized inner, but has no bends or joins, so it flows pretty well in my mind. No issues at over 40k now. I got that red hose from a specific hose place at geebung, I'm sure there's plenty around. Spent a lot tryiung to get the right fittings / hose size, and even the expereinced hose bloke was a bit perplexed as to how to do it "properly" hence my "nasty" sikaflex effort ( which is still just fine at 40k plus kms! )

[stormshark]

And I am led to believe by all this discussion that VW don't have some set service interval procedure to take care of this for those of us who do not wish to tamper with their TDIs in any way?

For those who want to tinker, this discussion is quite interesting and mostly informative, but for those who do not and just want to maintain our car's reliability (and above all, originality), what course of action is open to us?

I find it difficult to believe that VW aren't aware of the issue and don't have methods in place to manage it for the majority of TDI drivers out there.

I have brought this issue up with the service manager of my dealer, gave him copies of emails from here, regarding the problems. Their response was along the lines of "didn't i think VW engineers with resources and Cpy reputation would not have designed motors with these prevailing issues" etc etc Would not recommend aftermarket products such as Provent etc. I listened but got the distinct impression it was a snow job and they were aware of potential problems!

[tonymaroney]

OK...I pulled the rubber air inlet tube off the EGR+flap mechanism and had a look up inside the EGR valve. It's hard to see up there clearly, but using a mirror and strong torch I got a fairly good look. To be honest it didn't look too bad. The car has 60000klms on the clock, and while there is a distinct layer of oily crud up there the airway is pretty much fully free of obstruction. At the EGR inlet valve itself it looks very clean...matt grey with no oil and no lumps of crud, but below it and above it there was noticeable oily coatings. The photos I have seen on the net (from vehicles with the same mileage) are much worse than what I saw, and I get the feeling are probably due to poor fuel quality allowing lots of crap back through the EGR system, or some other problem. I have always used diesel conditioner and while this isn't specifically going to have an effect on the EGR, a cleaner combustion in the cylinder might not have sent so much rubbish back around to combine with oil coming in from the crankcase vent.
So I'm happy with the current condition of the EGR, but I am going to take preventative measures to make sure it doesn't get worse. Even a moderate coating like what I saw will help attract further crud build-up, and the Provent should help reduce that, or slow it down. I might still take off the EGR valve just so I can see up into the inlet manifold a bit better (...maybe it is worse than it looks up there..If I do this I'll take some photos), but otherwise Greg/Cogdoc's prediction that he would only expect to see issues for this EGR on a normal vehicle after at least 100K on the clock looks to me to be a very accurate assessment. If we want to get 300K out of the vehicle without having to do a clean of the EGR and intake manifold then a Provent sounds like a sensible way to go.

I'm not surprised that a service manager didn't agree with our assessment of the situation, and even less surprised that he/she didn't like the idea of fitting an unknown device to the car to reduce a problem that they didn't admit to in the first place!

By the way I checked out the cost of the gaskets and O-Rings needed if I were to remove the EGR system and inlet manifold...I was expecting to get quotes of $200 etc (just because I am used to being burnt )...but I was floored when I got the quotes: $3.70 for the O-Rings and $8.40 for the big manifold gasket!! I double checked that he knew what part it was (had a diagram with me) and he had my VIN number, so it was all correct. That's so cheap I am sceptical that there still must have been a mistake!!!

Cheers,
Tony

[CatonaPC©]

I have brought this issue up with the service manager of my dealer, . . . . "didn't i think VW engineers with resources and Cpy reputation would not have designed motors with these prevailing issues" etc etc Would not recommend aftermarket products such as Provent etc. I listened but got the distinct impression it was a snow job and they were aware of potential problems!

You are entitled to draw you own conclusions about what the service manager said, just as you are entitled to make your own decision about whether to re-engineer your car based on the opinions of people in this forum who didn't design the car.

And think very carefully. No service manager employed by any dealership would recommend any aftermarket product which would clearly violate warranty or anti-pollution laws or standard maintenance practice recommended by the manufacturer. And that's before we consider the legal and financial liability they would expose themselves to.

OK...I pulled the rubber air inlet tube off the EGR+flap mechanism and had a look up inside the EGR valve. . . .I got a fairly good look. To be honest it didn't look too bad. The car has 60000klms

My my my! Didn't look too bad after 60,000 kays.

So much energy has been expended in this thread passing out questionable advice about what to fit etc etc. that the the real gist of the thread has been lost. Should we be more concerned?

Well, I was once. Now I'm not. VW have built a pretty good car. I think I can rely on them to keep it that way.

[mikinoz]

You are entitled to draw you own conclusions about what the service manager said, just as you are entitled to make your own decision about whether to re-engineer your car based on the opinions of people in this forum who didn't design the car.

And think very carefully. No service manager employed by any dealership would recommend any aftermarket product which would clearly violate warranty or anti-pollution laws or standard maintenance practice recommended by the manufacturer. And that's before we consider the legal and financial liability they would expose themselves to.



My my my! Didn't look too bad after 60,000 kays.

So much energy has been expended in this thread passing out questionable advice about what to fit etc etc. that the the real gist of the thread has been lost. Should we be more concerned?

Well, I was once. Now I'm not. VW have built a pretty good car. I think I can rely on them to keep it that way.

I think the main thing that needs to be taken from this is that this is an enthusiasts forum. People here are interested in modification for performance/longevity etc.

People can take or leave the advice that is given on the forum. Anecdotally, there are known issues on this topic.

Each owner treats their car differently. I don't think anyone should be persecuted for choosing to modify or not modify in the setting of this forum.