My suspicion is that there is a certain amount of blow-by that needs to be managed. Feeding it through the turbo is a solution that doesn't require any action on the part of the driver. Having a separator/catch can means that maintenance needs to be performed. If not emptied, then it's a spill.
Not all MB owners even know how to open the hood much less manage a catch can.

I also think that keeping the seals fresh allows the design to work. When you examine the turbo inlet it is very clean, perhaps due to the rpm's and the oil bath.

When I bought the '08 and took the air tube off apparatus off, the gasket/seal was very loose as was the smaller one adjacent to it. I bought the large seal as well as the repair kit for the smaller pipe. Came with a beefier seal and a new heater.

The smaller tube is now firmly held in place and comes off with the plastic air tube.

My $0.02. Skippy

 

Those are good thoughts. It is very clean in there despite the oil pool. I have read about several people tearing down their diesels to fix the oil cooler seal and egr valve. Several reported that the intake manifold was gunked up with oil sludge and also the tubes from the intercooler had gunk in them. One of the guys posted lots of pics of his repair and the whole intake area was sludged up. That's why I'm leaning toward installing a catch can. You make an excellent point and maybe the reason MB designed it that way, in regards to lots of people never open their hoods. My nose is always under there even though I don't know half of what I'm looking at.

 

The turbocharger has oil plumbed to it for lubrication.

All engines have crankcase ventilation, which has to vent somewhere. Turbo or not, gasoline or diesel, its fed back to the intake for clean combustion rather than released as a pollutant into the atmosphere.

 

Washington DC ML,

Here's the link <

Bought from dealer.
p/n 642-094-00-80 - turbo seal $17
p/n 642-016-03-30 - PCV kit $56

>

Bear in mind this is for an '08 320CDI.
I see your sig showing a 2010.

Skippy

 

Thanks guys!

Interesting enough now with the part number you supplied I found this. Freightliner Sprinter 2500 Engine Air Intake Hose 6420940580 Genuine | eBay. This is the only part of the pipe that I really need.

Washington DC ML,

Here's the link <>

Bear in mind this is for an '08 320CDI.
I see your sig showing a 2010.

Skippy

 

Both part numbers will work on the 2010 according to MB's EPC net.

 

New discovery

Well if you search ebay for pcv items you will find that bmw and Volvo and others make pcv oil separation kits. Evidently they are factory installed on the cars. Wonder why MB doesn't do this??
I'm going to install one that I bought and direct the fumes back into the intake ahead of one of the air filters.

 

Going back to the original post - PCV (positive crankcase ventilation) is what you call that rubber thingy hose that ends up just ahead of the turbo. If you follow that hose - it leads to a circular plastic device that is supposed to separate oil and air. Unfortunately - it is not doing a very good job. So the only alternative is to install an oil catch can or separator. I only realized recently that other OM642 vehicles in Europe suffer the same problems as we do. Simply google "CRD catch can" or "300C catch can". Here are the benefits of reducing oil ingestion in the turbo.

1) Prolong life of Diesel Particulate filter (aka exhaust) - less oil in combustion chamber = less soot or unburned oil.
2) Minimize accumulation of gunk in the intake chamber/ports. We know the main source of carbon deposits/material is mainly dirt coming from our EGR system. Soot and other unburned exhaust gases accumulate when it is mixed with oil. Again, less oil = less soot is produced in the exhaust.
3) Reduce oil buildup in the intercooler = better breathing = more power
4) From what i read in CRD forums - gunk in the intake manifold might be the cause of burned out swirl motors (when the 6 vanes get stuck because of sludge/carbon).
5) Engine oil does NOT burn like diesel. So it does not "explode" as readily as diesel. So keeping engine oil away from the combustion chamber keeps your "burn" mixture more volatile. (cetane rating and flash point of oil is different)

Installing an oil catch can will not completely eliminate oil in the intake tract - but it will help. Results will vary depending on your setup. Also - some folks will argue "oil" protects valve seats. Again, oil will not be completely eliminated. Even so - all direct injection engines are already designed to have no fuel or lubrication ahead of the valve seats.

Lastly, don't rely on just this forum. Go around and check other forums like I did - we are lucky there are a lot of other OM642 users around the globe. In spite of these set-backs I still think this engine has a lot of potential. It just needs a lot of TLC.

 

If that pic is an ml, do you just run it without the engine cover? I figure on putting it just below the big fuse box although the fender well is plastic. I read where another guy just put the outlet into the air cleaner box ahead of the filter. He said he just gets a spot on the filter. That would make it easier to plumb.
Thanks for you comments on the benefits of taking the oil out of the intake. It's what I figured but wasn't sure as this is my first diesel. Volvo puts them on their gas turbos.
What is the electrical unit at the seal end of the pcv tube? Should I leave it in the line out?

 

Perhaps that's the reason for the higher ohm reading in the PCV heater in the repair kit. More heat to assist the oil vapor flow? It can't be a huge difference as the wiring to the heater is not changed and it's 'normal' size IIRC.
Skippy


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20swrt,
Have you had the separator in place long enough to talk about how it's working?
It looks like you've added it to the existing path from valve cover to the connection at the turbo inlet.
Skippy


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20swrt,
Have you had the separator in place long enough to talk about how it's working?
It looks like you've added it to the existing path from valve cover to the connection at the turbo inlet.
Skippy
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Short answer - no not yet. I just installed it yesterday before I take a long drive. You see, two years ago i posted this same question in benzworld and heeded the advice of some respectable members not to do it.

http://www.benzworld.org/forums/w164-m-class/1583289-how-does-ml320-cdi-separate-oil.html

But then - after 2 years of loosing 1+ quarts every 10K miles (bet oil changes) I decided to dig further. I noticed all the folks in other forums installing catch cans. Since it only takes 1 hour to install - I decided to try it out. I already had the catch can from my parts bin. It will take awhile before i can report back how much oil i collect. I dont expect to see miracles inside my intake manifold+DPF. Whatever is already there won't just disappear. I'm just hoping to avoid having to replace my DPF or swirl motor anytime soon.

This mod is easily reversible - It just takes a 5/8 brass coupler ($2 each at home depot). I did not use hose clamps (for now). I figure - since Im out of warranty - Ill just experiment on my own.

 

Actually the intercooler is downstream of the turbo. Filtered air enters turbo along with oil vapor. The turbo compresses the air and adds heat in that process. The compressed air travels through the intercooler where some of the heat is removed and then to the intake manifold.
So under low boost conditions the oil may settle in the intercooler. Some articles suggest forcing high boost will serve to clean the intercooler.
Anybody removed it to see what resides there?
Skippy


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I stand corrected. I thought the turbo was just compressing the chilled air into the intake. I did read a post where the guy took his intercooler tubes apart and there was some gunk in there.

 

I'm still 1200 mi away from home. So I have no plans to do anything to my little experiment (catch can). But based on what I immediately saw - I'm convinced I found out where most of my oil was going (PCV). I only have less than 70k miles so I don't suspect my turbo seals. Besides, loosing 1 qt every 10k miles is totally acceptable. I only did this experiment because I know a 2,400 mi all hi-way trip is a good opportunity to blow out any oil in my intercooler,etc.

Also, returning the collected oil is ok. But in my case, I used my old catch can and did not clean it before I installed on my engine so I think this oil is contaminated. It's not worth the risk.

 

please keep us up to date on how this is working for you, etc

i read a lot on the jeep forums about this and bought some kind of aftermarket catch can recommended over there

it is very big and we only found one spot to mount it, i have not put it in yet
the project kind of got put on the back burner

but finding hoses etc that were big enough, oil resistant etc was hard especially with the little bit of room there is in the engine compartment

so i have a lot of parts but have not done this yet

will be interested to hear how yours works out

if you could post some more pics of how/where you plugged this in to the air system that would be great

 

Same here. I bought the professional oil separator and it's pretty big. Only place I see to mount it is on the front fender well, passenger side, under that big fuse box. It looks like the outlet line will run along the side of the airbox on the pass side. Return line will be the problem so I'm thinking about just running the return line from the separator to the air box inlet on that side and plugging the port at the turbo intake. One guy on here did that and he says he just gets a slight spot on the air filter. My question is what is that electronic part at the turbo inlet?

 

The catch can works great for me. But like you said - its too bulky and looks bad. I'm considering using this BMW cyclone oil/air separator instead (picture). I think its small enough to hide behind the engine - but we need to install a remote oil reservoir and install that somewhere in the bottom of our engine bay. If this thing is as effective as my Dyson vacuum - then its the perfect solution for us.

cvincent - I simply cut the existing PVC hose and installed it in between like this link. If you want to go back to OEM you can simply buy the same part listed in the earlier part of this thread.

Provent install pics on 07 CRD - JeepForum.com

I'm finally back from Houston (2400 miles round trip). The "italian tune up" really does do wonders. I feel like the ML lost a lot of weight. Feels like a champ when pulling away from traffic. I averaged 28-29 mpg (72 mph).

 

ok I'll bite. What is an Italian tune-up? I put a can of Seafoam in my tank and it seems to run smoother. Could always be my imagination.

 

that is what i bought, the prevent that is in that link

and the only place we found to mount it is the left front area also

where i ran into trouble was finding oil resistant hose, there are lots of hoses that are thinner and would fit better but not oil resistant

we considered using bendable copper tubing, any thoughts on that?

 

Try searching for viton hoses. I drained the catch can and got 6 oz (almost 1 cup). I also inspected the return hose and could still see some oil residue. As expected, this setup still let some oil pass through on my 2400 mi trip.

The "cyclone" type oil separator I want to try does not have any restrictions (screen or filter). Here is a cutaway view. It works like a Dyson vacuum cleaner. It uses centrifugal force to trap the oil on the walls. I'm hoping is more effective than the one I am using right now.

 

ok i will look for viton

i really want to know how this other thing works for you, please keep us up to date

thanks

 

"Italian tune-up" is when you take a long drive. It somehow makes your car seem faster after the long trip. I really do not want to use any chemical on my ML320. I fear it might damage the DPF or injection system.

Just to update you all. I noticed i had some oil coming out of the top of the dipstick. This is a sign of increased crank area pressure. Most likely caused by the catch can i installed. The hose or can might be too restrictive - so I will need to make adjustments. I will try to re-position the can to make it shorter.

 

I read a number of threads on the Jeep CRD forum. Several had the same outcome of a pressurized crankcase venting through the oil dipstick tube.
Some commented that they thought the tubing was too small on their catchcan (3/8) and other considerations had to do with winter conditions. The cold could allow moisture to freeze inside the piping. The result was either going to the elephant tube vented to atmosphere or restoring the stock system for the winter.
Maybe the cure for blowby is less obvious than first thought.
Skippy


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I read a number of threads on the Jeep CRD forum. Several had the same outcome of a pressurized crankcase venting through the oil dipstick tube.
Some commented that they thought the tubing was too small on their catchcan (3/8) and other considerations had to do with winter conditions. The cold could allow moisture to freeze inside the piping. The result was either going to the elephant tube vented to atmosphere or restoring the stock system for the winter.
Maybe the cure for blowby is less obvious than first thought.
Skippy






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Aren't your hoses bigger than 3/8? Their size looks ok to me but I'm wondering if your can is not big enough. I've got the Pro Vent 200 which is pretty big for what I thought you needed. Their size is configured to engine size so maybe yours is too small. I'm going to put the Provent to the left of yours under that fuse box.(looking at your pic)
I would encourage all diesel drivers to look over that Jeep site and check out the links. Those guys have a lot of experience with catch cans, performance chips and oil analysis. The oil reports were particularly interesting. They seem to be more daring about trying stuff with their engines than we are.

 

The existing hose uses 5/8. I used the same diameter hose all throughout. If you look at all my pics I used no reducers and only 1 hose clamp. Even my catch can is 5/8.

I think I accomplished my goal of measuring how much oil can be collected on a 2400 mi trip. Now that I know, I can now buy something that can be well hidden and not look ugly under the hood. Nothing is off the table so keep your ideas coming. :bowdown: My plan is to really keep the hoses to a minimum.

 

20swrt,
The picture you have of the Provent system for '07 Jeep shows two catch cans. Did you install two on your 320 or just one? If just one it might explain why there was excess pressure.
Skippy


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OM642 oil mist air separator CCV

The OM642 does have in internal centrifugal oil/air separator, situated at the back of the intake camshaft. The Blow-by gases are fed via the oil separator through the hollow camshaft to the CDR valve

 

The OM642 does have in internal centrifugal oil/air separator, situated at the back of the intake camshaft. The Blow-by gases are fed via the oil separator through the hollow camshaft to the CDR valve

Thanks for posting this. Now the system is understandable.:thumbsup:

 

R320,
Useful info. Thanks.
I'm thinking that the effectiveness of the stock separator 'could' be compromised through normal accumulated deposits. I wonder if it's a serviceable device?
Tough location for sure.
I will point out that there is a kit from MB that contains a better gasket for the tubing from the separator to the turbo inlet area as well as a replacement heater. The heater has a higher ohm reading which suggests to me that it heats more.
This gasket is different from the large inlet gasket.
I reported better details on the kit in another thread.
Skippy


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The internal oils separator is not serviceable.
Also, the valve covers are also NOT recommended to remove, because is you do the entire head is recommended to be replaced aswell from MB.
Reason being that the valve cover also acts as the bearing seats to the camshafts.

 

R320,
Useful info. If not serviceable then likely not something that commonly breaks or wears.
So, the folks who are experiencing or researching alternative methods to control their excess blow by might be in the right track?
Seems to me that something else might be at play.
Skippy


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Must Read CCV OM642

This CCV system has been an expensive problem for all of the OM642 owners: Chrysler / Sprinter owners alike. It should be MB's responsibility to address this issue of design.

MB CCV solution seems well intentioned and sound on paper, but unfortunately this CCV system has not provided the longevity that we have expected from MB.
-----

MB Design:
It is important to not have the CCV vapors freeze.
Ice crystals destroy turbo intake blades, and oil/water emulsification forms when CCV vapors come in contact with cooler temperatures.
Unfortunately, the colder it becomes the more contaminates the blow-by gases contain. Having an effective CCV solution that functions in colder weather is always desirable. MB has achieved this end with it's existing CCV system including it's short CCV outside tube to the turbo PN: 642-010-18-91
MB idea: heated/enclosed/service free/centrifugally controlled blow-by oil separation. BUT....

Problem:
The volume of the 0M642's blow-by gas exceeds it's design volume parameters as the engine ages. As blow-by volume increases with age so does crankcase pressure.

The aging 0M642 begins to create more blow-by volume as the piston rings and engine tolerances begin to increase, (soon after 80k km).
The blow-by gas volume over powers the internal centrifugal oil separator's capacity limit.

The inability of the OM642 CCV system to separate increased oil mist volume from the CCV system as the engine ages ...ever slow-slightly increases blow-by pressures, which manifest themselves at the weakest point... the oil cooler seals. That is why MB issued the new THICKER vitron oil seals.

It's well known: referenced:
Mercedes-Benz OM642 - Wikipedia, the free encyclopedia
"... In addition to the oil cooler seals; this engine can also have an issue with the design of the positive crankcase ventilation system." THEY are related.


Real Life Practicality:
• Why are there not 2 centrifugal separators?
One for each bank of cylinder heads, on each intake camshaft.
Rather than just one?
They would both be able to connect to the turbo inlet at the same junction.

----------
Owner's Facts:

• Catch cans cause oil seals to fail pre-maturely.
(increased CV pressure through restricting blow-by gas volume.)
BAD

• External oil water coalescing filters freeze.
Causing pre-mature engine damage through cold weather and lack of service.
(They are expensive and add to the already high serviceability issues)
Raco/Pro-Vent/Fleet-Guard...
BAD

• Atmospheric Venting OCV: Also reduces engine life by introducing un-filtered air and contaminates directly into the crankcase, causing real internal sludge.
(Not to mention the ecological issues)
BAD

It's Diesel not GAS...
• The "Italian Tune-Up" is not advisable on diesel engines, especially an OM642 with over 80k km, as you raise engine RPM you also increase the blow-by volume and pressure and the amount of contaminates in that blow-by... that will pass oil mist into the entire intake system... (not cleaning it, making a oilly volcanic mess)

1500 rpm produces 1g/hr of blow-by (with clean air filter)
2500 rpm produces 67g/hr of blow-by (with clean air filter)

2500 rpm produces 232g/hr of blow-by (with dirty air filter)


• Maintain you air filters in PRISTINE condition ALWAYS!!
This really is your only defense against CCV pressurization.
GOOD

• Double the frequency oil changes after 100k km and replace oil filters individually after severe operations.
GOOD

Myths:
• Turbos do not need lubrication via the CCV, if you see oil on your turbo intake seal... that's not a good sign.

• Oil/water mixing with the EGR system is a CLOGGING chemistry to any intake system, so keeping it out/low means a cleaner intake.

• Why no centrifugal oil cleaners on this motor, or after-market heated - electric drive centrifugal CCV oil/separator similar to the VOLVO D11 - D13 system.

Honorable Mention:
We all need to thank the countless hours of our friends in the JEEP and SPRINTER world for all their dedication and persistence to their trust in their OM642s.

 

R320 - thanks for all that valuable information. What you said further strengthens my resolve to find a solution to this problem. So we both agree the existing MB oil separator is inadequate and insufficient. We also agree that the EGR just makes it worse. In as much as we all think MB should fix this problem, I really don't think they will. Why ? Its not a safety issue. Also, MB is not bound by contract to make these engines last > 100K miles.

So, we are on our own in fixing this issue. :surrender: Based on my first hand experience, i collected 6 oz of oil after a 2400 mile trip. That is a lot of oil. I simply cannot just wait for MB to issue a recall, fix or redesign to the OM642 CCV for our 7+ year old vehicles. Many thanks to you I will remove my catch can. Mainly because ice could form and end up in the turbo.

So now I am thinking about plugging the turbo intake port and installing a filter just after the CCV (atmospheric venting). That might avoid dirt ingestion. I always thought air only went out in one direction. Does air go the other way (vacuum) too ?

Also, Can you clarify your statement below ? Did you mean that it is NOT a myth ?

Myths:
• Turbos do not need lubrication via the CCV, if you see oil on your turbo intake seal... that's not a good sign.

 

MB should issue recall

MB should issue a recall to replace the LEFT intake camshaft with one that has a similar design to that of the right camshaft.
A hollow LEFT intake camshaft with an integral centrifuge oil separator connecting to a separate CDR Valve and vent tube to the turbo inlet as PN: 642-010-18-91.