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Discussion Starter #1
There have been many discussions about crankcase breather oil going into the air intake system, the leaks and problems it brings etc. I am considering installing an oil collector to remove the oil before it goes into the turbo. My question is: is this oil needed for lubrication of the turbo? It's going into the intake vanes so does it really lubricate anything? It doesn't seem like it is a good thing to me but MB mechanics will tell you that that is the way Mercedes designed it so it must be needed. Isn't there an oil supply to the turbo bearings?
 

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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
 

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Discussion Starter #3
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.
 

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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.
 

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Hey, do you have the part number for the repair kit. I've not been able to find that part anywhere.


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
 

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Discussion Starter #9
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.
 

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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.
 

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Discussion Starter #13
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?
 

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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.
 

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Discussion Starter #15
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.
I don't know what drivbiwire is talking about. The intercooler is upstream of the turbo and I don't see how oil vapor could go into the intercooler. It would be going against the Jetstream of air. The oil we are concerned about is coming from the pcv tube just in front of the turbo. I think you got some bad advice there. I wonder if anyone has replaced that "hockey puck" and had success??
 

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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 wonder if anyone has replaced that "hockey puck" and had success??
Even if that puck is not 100% effective, I don't suggest removing it. That "puck" separates oil AND returns the oil back into the camshaft area. Whereas my oil catch can does not return oil. In that aspect, the "puck" is still better. And yes SkippyJasper is right about the intercooler being downstream after the turbo.

I drove 1200 miles last Sunday. I see about 1/8 to 1/4 cup of blow-by oil collected (viewed from the sightglass). I will know for sure after I drain the container later. That oil will never return and be discarded.
 

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Discussion Starter #18
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.
 

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Discussion Starter #19
Even if that puck is not 100% effective, I don't suggest removing it. That "puck" separates oil AND returns the oil back into the camshaft area. Whereas my oil catch can does not return oil. In that aspect, the "puck" is still better. And yes SkippyJasper is right about the intercooler being downstream after the turbo.

I drove 1200 miles last Sunday. I see about 1/8 to 1/4 cup of blow-by oil collected (viewed from the sightglass). I will know for sure after I drain the container later. That oil will never return and be discarded.
That's a lot of miles in one day. I was wondering if a newer "puck" would perform better. Why don't you pour that collected oil back into the crankcase?
 

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