Took the plunge.....

[gumby6371]

A very good and valid point Welly, unfortunately my confidence with the spanners deserted me at that point.

If anyone fancies posting a guide on removal and proper cleaning I'd probably give it a go but don't fancy tackling it blind.

[Welly]

Here's a BMW fanimold blockerage:



And the inlet ports of the head further down:


Info found here: http://bmwspecialistreading.co.uk/

Like we've said before Diesel EGR is not very nice, this sort of build up can occur at 60K miles. A 'major' service should really include a full strip and de-coke in my opinion (add that to your MPG spread sheet ).

I'm amazed that chunks of that rubbish don't fly off and get eaten by the engine, maybe they do and maybe that accounts for poor performance sometimes.

[jonsowman]

I used a thin eBay aluminium plate at the EGR end, I'd guesstimate at 1.5mm and the existing blank at the other end was little more than coke can thick.
The pipe itself was blocked solid with gunk and I'm guessing the EGR was as well but as it was only for show I didn't bother inspecting or cleaning anything properly.
As you say leaving the EGR and pipework in place it eliminates the need for anything more solid as its clamped all around the edge to stop any distortion and potential leaks. Daubing everything in high temp liquid gasket helps as well.

Assuming that your coupe layout and access is similar I'd give yourself an hour to complete the job at a steady pace with smoke and brew breaks and half an hour to apply the plasters

If you have a strut brace that will need to come off so if you're planning to lift the car do that first and replace the bolts before lifting and avoid the struts dropping down, apologies for stating the obvious but easily forgotten if your anything like me, thats why I kept her on the ground.
I'd advise you remove the EV mount from the bulkhead next and cable tie it to the wiper arm (or other available place of safety) to keep it out of the way and avoid having to label and unplug anything.
I managed to wiggle my arm and a ratchet down the side of the engine to access the turbo pipe bolt and jubilee clip (1/4 inch ratchet with 50mm extension bar and 10mm and 8mm sockets IIRC) then the airbox end and the mounting point bolt and it should be free.
No water jacket on mine so I removed the EGR and pipework in 1 piece, from memory 2 bolts at the EGR, a bracket on the back of the block and one just above the swirl actuator and the 2 bolts on the intake manifold.
This is a bloody good time to change your swirl actuator if its suspect or at least pull it apart and check the diaphragm. I undid the mounting bracket just below the vac pump (2*10 mm bolts) as the last screw that holds the actuator is impossible to access in situ. In hindsight I would have changed all the rubber in the vac system with everything out of the way but of course I did it the hard way and still haven't done the turbo actuator pipe as the 2 pipes you will be removing are the ones that block access!

All this info is in Finchy's guide as you already know but a little confirmation never hurts!

Thanks for this, as you say, the confirmation is very helpful I will do this as soon as possible I think, I'll go for the 1.2mm ali plates for both inlet and outlet. Going to be a few weeks before I have time to get round to it though I think

[mjb]

If the EGR pipe (leading to the Manifold) is caked in crud then doesn't it follow that the Inlet Manifold itself will be caked up inside? I've not noticed anyone say they've removed the IM to do further cleanage?

It's very much on my todo list for the mrs' car, especially given the EGR pipe was completely well and truly blocked

[mjb]

And the inlet ports of the head further down:

How do you go about cleaning this such that you don't end up with a huge pile of sh*t in your cylinders?

[Doggy]

Easy - take the head off.

[madmadmax]

the other way is to clean the runner withe the valve closed then once clean blow out with a bike pump or compressed air

[Welly]

See how the crap has built up more on the outside of the bend, this makes sense as the air will travel faster around the inside line and not be able to deposit the crap so easily. Fair old restriction though all the same and all thanks to EGR.

In complying with the EURO emissions they must have known the diesel engine will kill itself eventually but carried on through demand and the lack of any alternative (tiny petrol turbo's) in theory if you bought a modern EGR'd diesel then at 50/60K miles you'd have to strip the head, skim it, refurb the valves, thorough decoke and a bill for a couple of grand

[gumby6371]

Taking Welly's comment a step further I can only conclude one of the following;
a) current emission controls are poorly engineered as a knee jerk reaction to the regulations
b) they are well engineered to ensure additional revenue from dealership servicing whilst appearing to be tackling the ecological issues.

If I were a betting man option 'b' gets my money.

I understand the engineering principles behind the EGR and I also understand the principles of fitting an intercooler to a turbo charged diesel engine but I have never understood why you would fit both as they are counter productive.
A clean engine is more efficient therefore produces more power for less fuel consumed therefore has lower emissions.

If any of you follow F1 its a case in point that the Merc's are more powerful and also more fuel efficient.

[Welly]

The EGR function is to reduce combustion temperatures because they recognised a long time ago that high combustion temps mean high NOx emissions. It's a bit of a compromise because it only uses EGR at low throttle openings and at idle, when you accelerate it closes shut and doesn't do anything.

EGR operation is also a bit hit-and-miss as the recirculated waste is piped back into a common header (inlet manifold) so it is not possible for each cylinder to receive an equal amount, ideally each cylinder should have its own EGR drivers will also report a 'delay' when hitting the throttle and this is due to waiting for the EGR piping to clear and the cylinders to get proper air for combustion. EGR on a diesel is literally like driving your own waste collector....eventually it'l get full up.

This is why I switched back to Petrol, I'd have a Diesel but it'd have to be very new and be gone by 50K miles (not an option for me due to cost and low mileage use).

[madmadmax]

egrs on a diesel engine are not fit for purpose but its making the manufactures and government seeing it that's the real problem

[Flor1n]

....and outed the egr and air dosers.

Some goodies I collected

The bits tied together with red tape are a set of 'Nico pipes', as used by coupe 'super tractor' owners to replace the air dosers.

I used the left-hand flanged pipe, but instead of chopping up the lower hose that links the turbo boost pipe to the bottom of the intercooler and the bypass heat exchanger, I simply substituted a 110 HDi turbo / intercooler hose, (which fits perfectly), as discovered by my learned friend, gingermagic.

The three plates in the foreground are, from L - R, 3 mm thick steel egr blanking plate for egr valve / exhaust manifold, 2 mm steel plate for egr pipe / inlet manifold and Doggy's secret weapon, a 1 mm thick aluminium plate I fashioned myself, using the others as patterns.

Right - normal layout, beforehand

and possibly the world's gunkiest intercooler / bottom boost hose.

A view of the air dosers, note the oil contamination on the lower of the two vacuum capsules
The vacuum pipe was very loose.....

..as were the hose connections at the bottom of the intercooler and the bypass heat exchanger.

......and after

The 'Nico pipe' in place - I haven't removed the bypass heat exchanger yet as this involves re-routing the coolant hoses. Thought I'd make sure everything's tickety-boo first.
View from the other side - can you spot where the egr blank is fitted?

Not very obvious.
Hoping this will sneak through if they start getting anal about this in MOTs

A few bits I don't seem to need anymore......


After a short test drive, it all seems to work just fine. Maybe a tad less turbo lag, seems more eager at very low revs.

I haven't changed the software as yet, (this is preparatory stuff to enable me to enhance things if I decide to go further). I thought it might complain about the airflow but so far it's happy. The electrovalves are all still in circuit, but those associated with the air dosers and egr valve now have no vacuum supply. This significantly simplifies the vacuum system, leaving less to go wrong.

I'll try to get some miles on it before doing anything further.

Hi, please can you tell me the dimensions of the pipes? or where did you buy them? I will try to follow what you have done here.