WH Diesel EGR Disable or Leave it alone.

[hotqld]

The EGR is mentioned by some the cause of inlet manifolds clogging up with soot causing expensive issues for the WH diesel.
I have installed a catch can for the crankcase breather / swirl motor issue.

Reading thru what the USA guys are saying is:
1/ The problems can be caused by babying the WH diesel ...diesels like being driven a little harder?
2/ Wrong engine oil allowing soot to build up.
3/ Disable the EGR and the DPI life will be shortened ...whatever that is, but they reckon its expensive.

Is sooting up of the inlet manifolds a big problem?
How often is this really happening, some WH diesels must be recording high milages now 300,000 klm plus.
My last visit to the dealers / service manager his comment was the WH diesel motor is terrific the only thing they see on a recurring basis is glow plug and swirl motors.

So is the suggestion of EGR disarment really warranted and if it is how without spending a grand on the green ECU flash?
Or is there some maint we can do to clean the inlet manifolds?

[fester]

If you jump on some of the MB forums particularly heavily UK based ones you will see the EGR is a big issue.
It is oil full stop mixing with the EGR soot regardless of oil type. You have already addressed the oil blowby as long as your catch can is a good one, most aren't. You will however have a decent build up of crap in there which narrows the inlet tracts. On my 2.7 it was at least 5mm thick in the manifold runners and right down to the valve. The UK boys are either removing the manifold to clean or running a cleaner through it and reporting better running.

Fix is about $2.00. Not sure what it does to the DPF ( diesel particulate filter) but depending on year you probably don't have one and won't affect the cat.

Given you've addressed the oiling you could probably clean and not worry unless the EGR plays up. No talk of DPF issues on UK forums. There is huge read over there for you to make your own mind up but I still don't like the soot going through the engine.

In relation to the oil blowby cleaning out the intercooler is handy as well cause with the oil coating the internals of the cooler it will to some degree reduce the heat transfer of the air. Again maybe small but if you ever have it all unhooked good time to attack for extra piece of mind.

[captjim]

Hi,
I rebuilt an om642 out of a wh at 67000ks and the inlet manifold had atleast 6 to 8mm of tar coating. I've also rebuilt Ranger and COlorado motors that were similar. I fitted a catch can but it kept worrying me so I went for the Gde tune and egr delete for the long term performance.
Capt Jim

[hotqld]

So on the inlet side we have the EGR delivering some dry soot and exhaust gases to the inlet manifolds, not a problem in itself? but introduce crankcase by pass wet stuff, that then reacts to form a sticky mess in the inlet manifolds.

Would humidity then have an effect and do similiar? Which might explain why this is a problem in the UK...never stops raining?

My catch can is German Manufactured from Sydney Filters.
The filter in the catch can should be replaced, How often?
Every oil change? 12,000 klm?

Or my logic is suggesting disconnect the inlet to the catch can and let just a little dry air get sucked into the inlet and let the crankcase bypass exhaust to atmosphere.

[captjim]

In the old days with marine motors we ran the breather hose into a coke can and it was close to full every 300 hours. I tried the elephant mod in the WH but it stank , put out quite a bit of smoke and dripped on the garage floor. My experience with Detroit and Mtu marine motors ,they require stripping the inlet manifold and intercooler every 750 hours to remove the sludge. The other problem is this tar gets quite hard and can break off and damage valves or worse pistons. I m sure it also could jam the swirl valves and thus damage the swirl motor. The GDE tune saves all the worry and gives heaps better performance.
Capt Jim

[Clarky]

I was researching scan gauges and came across a post (I think it was a UK 300c forum) where it said the EGR was closed most of the time and only noticed it open when driving around town at low speeds.
If this is the case someone who tows of does regular hwy speeds should not suffer from excessive sludge build up.
If I can find the site again I will post a link.

Can the EGR just be blocked leaving the valve and solenoid in place or will the computer detect this and throw a code?

[fester]

Originally Posted by hotqld

So on the inlet side we have the EGR delivering some dry soot and exhaust gases to the inlet manifolds, not a problem in itself? but introduce crankcase by pass wet stuff, that then reacts to form a sticky mess in the inlet manifolds.

Would humidity then have an effect and do similiar? Which might explain why this is a problem in the UK...never stops raining?

My catch can is German Manufactured from Sydney Filters.
The filter in the catch can should be replaced, How often?
Every oil change? 12,000 klm?

Or my logic is suggesting disconnect the inlet to the catch can and let just a little dry air get sucked into the inlet and let the crankcase bypass exhaust to atmosphere.

Humidity has no bearing on it. Reason it is so prevelent on UK MB forums is the shear number of models with the diesel in it and mostly being cars they don't seem to be into much the idea of catch cans etc. Most are disabling the EGR but not worrying about oil blowby.

I presume you are talking about the Provent or similar which is good, too many people put too much faith in those Supercheap/Autobarn catch carns which are just simply empty cylinders whihc allow the oil to blow in then blow back out again. Fill them with something and they are better but no where near as effective as a Provent.

If I understand your logic you are going to disconnect the catch can from the breather thereby allowing the engine to breath through the cartch can whilst the breather from the engine is just going to vent nowhere (atmosphere) Firstly that is illegal and will smell. Secondly if you have a quality catch can like a Provent then really you are achieving nothing and really going backwards. Thirdly you may be introducing unmetered air flow to the engine which may affect tuning (Not sure on WH) as you may be bypassing the AFM.

The soot is also having an effect on the MB swirl flaps. In the 2.7 Jeep the manifold is alloy, in the MB it is plastic as is the case witht eh MB 3.0. I'm not sure about the Jeep 3.0. The abrasive nature of the soot and the tackiness of the tar is what destroys the swirl flaps in the MB being all plastic, hence they are also removing the swirl flaps, plugging the holes and disabling the swirl motor instead of paying through gthe nose to replace. Again this is a $2.00 fix if you don't want a GDE tune.

A lot of Mb guys are removing the manifold to clean but it's a fairly time consuming and messy job. Wynns have a product EGR3 and more recently EGR4 which you squirt in while the motor is runnign and it cleans it out. some don't like the idea of this going through the motor but in fact many workshops and dealers are using this product as most new diesels suffer this. In fact Mitsubishi has redesigned the manifold on the Triton/Challenger to move the sensors out of the direct path to stop them clogging and have replaced some under warranty. Wynns in Australia are mainly selling the product to the trade so it's harder to get here.

Here's info on the swirl motor disable.
http://forums.mercedesclub.org.uk/sh...ad.php?t=97061
and the EGR disable if you have electronic EGR
http://forums.mercedesclub.org.uk/sh...ad.php?t=88374
and this one was for the 2.7 with vacuum actuated EGR and if the early 3.0's had vacuum I think it works for that as well but best to read yourself as it's been ages since I did this.
http://forums.mercedesclub.org.uk/sh...ad.php?t=68928