EGR horror!

Submitted: Thursday, Feb 05, 2015 at 11:42

ThreadID: 110999 Views:8021 Replies:9 FollowUps:8

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zimbo FOX

Hey guys just thought I would share my experience of removing my intercooler (install a new one) on my 2011 2.5TD D22 Navara, and too my horror the black crap that was hiding in my intake actually scared me, now I am no mechanic and don't pretend to be but have basic knowledge from playing with my R32 skyline.
When I initially pulled the cooler off there was a light coating of black sludge around the piping which didn't surprise me too much but i thought id stick my finger in a see whats actually a bit deeper in the pipe and wish I didn't, but glad I did, very thick black sludge.
I had a block off plate that I bought a while ago and was tossing up whether to install it, there are a lot of contradicting stories and ended up just leaving it off.
But I can tell you know do not listen to what you read, go right now and remove your intake/check piping and if its the same as mine you will not believe your eyes. Now this could be an isolated instance but my car is relatively new, never missed a service and has 80,xxx kms, but have also heard of many people having the same issues.
Now I'm not telling you to do anything, but after what I just saw I will not think twice about installing my blocking plate.
Cheers

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Reply By: zimbo FOX - Thursday, Feb 05, 2015 at 11:43

Reply By: TomH - Thursday, Feb 05, 2015 at 13:26

Reply By: pop2jocem - Thursday, Feb 05, 2015 at 15:28

Thursday, Feb 05, 2015 at 15:28

EGR systems were introduced to assist in the reduction of nitrogen oxide gas in the exhaust. Basically inert gasses from the exhaust are introduced into the combustion cycle to reduce temperatures that allow the formation of this bye product. Unfortunately this also reduces the performance of the vehicle to a degree.
I believe that like tampering with any other of the emission controls of an engine, this, strictly speaking, is illegal. Probably why a fault is recorded on the ECU of many vehicles.

I have read that research into other more efficient emission reduction strategies are making the use of EGR less favourable.

Cheers
Pop

AnswerID: 545407

Follow Up By: pop2jocem - Thursday, Feb 05, 2015 at 15:40

Thursday, Feb 05, 2015 at 15:40

Just as an addendum, the reason why we now have particulate filters added to the exhaust systems of diesels is that by using EGR the combustion efficiency is reduced. This allows greater particle (soot, carbon) production. This harmful emission must therefor be filtered out.
More and more engine manufacturers now specify fully synthetic lube oils. I suspect this is because of the increase in particles being washed down the cylinder bores and the extra dispersant ability required by the oil.

Cheers
Pop

FollowupID: 832974

Follow Up By: zimbo FOX - Thursday, Feb 05, 2015 at 21:49

Thursday, Feb 05, 2015 at 21:49

I don't disagree with the legality of blocking it, or do I pretend to know a great deal about the whole system, all I know is that it can't be good for the efficiency of the engine and the engine in general. If I found that black substance in the intake of my Skyline the engine would have already blown.
It surprises me how different everyone's view on the whole egr system, it worries me a bit that there is so much contradicting evidence to both sides.
Will have to pick my mechanics brain tomorrow.

FollowupID: 832993

Follow Up By: pop2jocem - Friday, Feb 06, 2015 at 02:43

Friday, Feb 06, 2015 at 02:43

zimbo,

Legal or not, many do the mod of fitting a blanking plate. With the vehicles that then do record a fault code some fit a plate with a small enough orifice to prevent the majority of the exhaust gas passing into the intake system but large enough to keep the system happy and not record anything.
Does EGR contribute to a reduction in efficiency? In my opinion it must.
My take is that, legality aside, fitting a blanking off plate either a complete blank or the control orifice variety will increase the operating efficiency and should keep the lube oil in better condition for longer.
From a strictly legal point of view you are reducing the effectiveness of the manufacturers attempt at NOx control.
By all means have a chat with your mechanic, but at the end of the day the decision is yours.
If it's of any comfort though, you ain't alone. (;=))

Cheers
Pop

FollowupID: 833000

Follow Up By: Ron N - Friday, Feb 06, 2015 at 16:28

Friday, Feb 06, 2015 at 16:28

EGR can be rated as a modern "failed technology". There are plenty of engine manufacturers who don't use EGR technology.
It's a dead-loss idea, and it provides nothing but headaches and increased maintenance and repair costs, to anyone who owns a vehicle fitted with it.

Cheers, Ron.

FollowupID: 833051

Reply By: Michael ( Moss Vale NSW) - Thursday, Feb 05, 2015 at 17:42

Reply By: Batt's - Friday, Feb 06, 2015 at 00:46

Reply By: Rangiephil - Friday, Feb 06, 2015 at 10:16

Friday, Feb 06, 2015 at 10:16

EGR is only open when the engine is under light load say cruising at 100Kmh.
Under any heavier load it is closed by the ECU.
While the EGR valve can be a restriction in some engines, it is really doubtful that the EGR valve will cause a drop in efficiency of the engine under full load conditions, as it is closed.
In my case I took off my inlet manifold on my Land Rover TD5 at about 140Kk and there was a lot of coke on the valve itself and that black crap in the manifold.

However a clean with a scraper and Gerni saw most of the coke transferred to my face and hair in no time.

The main thing to watch with aTD5 anyway is that the MAP sensor does not become gunged up. I believe that this is also a problem with VMs in Jeeps, 3.0 Patrols , and Mitsubishi Pajeros and probably others.. My wife's cousin had his Mitsu go into limp mode while going up Cunningham's gap towing a van. Mitsubishi replaced the manifold with a relocated MAP AFAIK .

I have left mine in place and just monitor the MAP , and using full synthetic diesel oil it has not become coked again in 35KK. They EGR tends to coke up cars that are not run hard eg stop start around the city.
I have a delete kit but I am loath to fit it, because of possible fault lights and the fact that in a Land Rover the bolts holding the EGR plate to the exhaust manifold are known to shear off when being undone, which would be sure to happen to me.
And I don't really think it affects performance one bit.
Regards Philip A

AnswerID: 545462

Follow Up By: Rangiephil - Friday, Feb 06, 2015 at 10:22

Friday, Feb 06, 2015 at 10:22

BTW, most EGR is fed in after the intercooler.

Oil in the intercooler is usually from the crankcase breather as previously posted.

One ( the main?) cause of excess oil in the inlet manifold is degradation of the Manifold Depression Valve or otherwise known as the PCV valve.
This closes off the crankcase vent under high manifold vacuum, ( as it is pre turbo, that means high load) even on a diesel, and stops excess fumes from entering the manifold.

If it is degraded/old it will not stop a lot of the oil entering the manifold.
They are usually cheap and a good investment if a car has done over 100KK.
Regards Philip A