C250 Crankcase/PCV Valve
#1
Senior Member
Thread Starter
C250 Crankcase/PCV Valve
Noticed a few issues while changing the oil over the weekend. Oil deposits on the air intake hose, dipstick is showing some rust build up on the upper section of the wire, and some oil seepage around sensors and cylinder head cover. I suspect perhaps a blocked PCV causing over-pressurization of the crankcase. I have attached a couple of pictures showing the general location and a closeup of what I believe to be the Crankcase Ventilation or PCV valve. You can see what appears to be oil from this part on the air intake hose. I can't find any references to the component or its part number. Can anybody help?
2013 C250 162,250 miles
2013 C250 162,250 miles
Last edited by alynch; 01-19-2021 at 12:18 PM.
#2
Senior Member
My 2008 C200K with supercharged engine does not have a PCV and I suspect your engine will be the same.
#3
Member
Your car has both a breather hose check valve that acts in place of a PCV: https://www.fcpeuro.com/products/mer...ebi-2710180329
And you also have an oil separator: https://www.rockauto.com/en/moreinfo...05193&jsn=1389
And you also have an oil separator: https://www.rockauto.com/en/moreinfo...05193&jsn=1389
#4
Member
Your car has both a breather hose check valve that acts in place of a PCV: https://www.fcpeuro.com/products/mer...ebi-2710180329
And you also have an oil separator: https://www.rockauto.com/en/moreinfo...05193&jsn=1389
And you also have an oil separator: https://www.rockauto.com/en/moreinfo...05193&jsn=1389
Richard
#5
It seems like I have the same exact issue
I recently noticed some oil seepage/deposits from the same exact area as the red circled area and some seepage from cylinder head cover.
will follow this thread for the eventual solution for this problem along with the other threads for the other 63 problems my w204 has at 70k miles
I recently noticed some oil seepage/deposits from the same exact area as the red circled area and some seepage from cylinder head cover.
will follow this thread for the eventual solution for this problem along with the other threads for the other 63 problems my w204 has at 70k miles
Last edited by spb147; 01-10-2023 at 02:32 PM.
#6
Check turbo oil return line
Hey guys, I had to replace the o ring for my turbo oil return line as it was manufactured poorly and started leaking around 130k miles. They made an updated part number. I just replaced the entire line as it was cheap. It may be unrelated to your issue but check the line. It is behind that area you are working on and there was oil everywhere leaking down the side of the engine too. There’s you tube videos of it too.
#7
Hey guys, I had to replace the o ring for my turbo oil return line as it was manufactured poorly and started leaking around 130k miles. They made an updated part number. I just replaced the entire line as it was cheap. It may be unrelated to your issue but check the line. It is behind that area you are working on and there was oil everywhere leaking down the side of the engine too. There’s you tube videos of it too.
will clean the area and see if its leaks independently of the turbo line that was fixed
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#8
yeah I degreased mine just have t checked back to see if there’s oil spraying everywhere still
#9
Senior Member
Thread Starter
In my case, the cause of the leak was the oil line to the turbocharger (red circle). There is an updated part number for the banjo bolt, which I installed, and at least this particular oil leak was resolved.
#10
So nothing to do with lack of Crankcase Ventilation or defect with the breather hose check valve/PCV and/or oil separator?
just as simple oil leak from the turbo line?
#11
Senior Member
Thread Starter
Yes, it was just oil spraying up onto the hose from the banjo bolt fitting. Well, not the banjo bolt itself but the o-ring on the end of the oil pipe that attaches to the cylinder head. I changed out the banjo bolt when I installed the new pipe with the new o-ring.
Last edited by alynch; 01-17-2023 at 03:13 PM.
#13
also worth mentioning the banjo bolt can be bought with the line and new orings for like 30$ on FCPEuro I think it was. Much easier this way because it comes with plastic tabs to center the washers so you don’t drop anything.
I attached my photos for anyone doing this project. Has old part numbers vs revised. The complete piece is easy to replace. There were torque specs somewhere on this site as well.
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spb147 (01-18-2023)
#14
Senior Member
I also replaced the turbo oil supply pipe. At first, I just bought the gasket and the banjo bolt from German Auto Parts but ended up buying the entire pipe from Mercedes.
I still yet to find where the PVC, crankcase vent valve, located on the engine block. I took out the air filter housing hoping to access it but it's not there, not sure if the intake manifold has to come out or not.
Even with the engine diagram, I have not able to locate it.
I still yet to find where the PVC, crankcase vent valve, located on the engine block. I took out the air filter housing hoping to access it but it's not there, not sure if the intake manifold has to come out or not.
Even with the engine diagram, I have not able to locate it.
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spb147 (01-18-2023)
#15
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2012 Mercedes C250 1.8 Turbo
2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles
Hi all,
I have a similar, if not the same issue. I have a 2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles.
My mechanic mentioned after service that my old oil has a strong gas smell. We also needed to replace the oil dipstick as it was very rusty and the steel strands already started separating in some places.
So, water vapor in the crank case and gas accumulation in the oil. No other symptoms at the moment. No smell, no roughness, runs smooth and powerful, no visible oil leaks.
The internet, the forum, and some of my colleagues say: check the PCV system first. So the crank case ventilation system - as this seems be be caused (hypothesis) by the accumulation of minimal blow-by during combustion. The blow-by can contain unburned gas as well as water vapor. If not extracted to the air intake manifold, it can cause overpressure in the crank case as well as the other symptoms described above.
My mechanic whom I trust strongly suggested to sell the car. My take on this is that any car I might buy as a replacement will be at least as much more expensive as any repair on this car can be and I already know this car and like it, too. So before I take the car to CarMax, I'd like to try a few things, beginning with the PCV system.
Going from simple and cheap and complex and expensive I would believe the following makes sense (up for debate):
Did I miss anything? What else should I consider to look at?
I have a similar, if not the same issue. I have a 2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles.
My mechanic mentioned after service that my old oil has a strong gas smell. We also needed to replace the oil dipstick as it was very rusty and the steel strands already started separating in some places.
So, water vapor in the crank case and gas accumulation in the oil. No other symptoms at the moment. No smell, no roughness, runs smooth and powerful, no visible oil leaks.
The internet, the forum, and some of my colleagues say: check the PCV system first. So the crank case ventilation system - as this seems be be caused (hypothesis) by the accumulation of minimal blow-by during combustion. The blow-by can contain unburned gas as well as water vapor. If not extracted to the air intake manifold, it can cause overpressure in the crank case as well as the other symptoms described above.
My mechanic whom I trust strongly suggested to sell the car. My take on this is that any car I might buy as a replacement will be at least as much more expensive as any repair on this car can be and I already know this car and like it, too. So before I take the car to CarMax, I'd like to try a few things, beginning with the PCV system.
Going from simple and cheap and complex and expensive I would believe the following makes sense (up for debate):
- check and replace the breather check-valve (where is this located and what is the part number?) - is this part 35 in the above image?
- check and replace the electrically actuated PCV valve (where is this located and what is the part number?) - does not seem to be in above image...
- check and replace the oil separator on the firewall side of the engine. Word has it that the high pressure fuel pump must be removed in order to get to it. (where is this located and what is the part number?) - also not in above image
- optionally, check, clean, and replace all breather hoses
Did I miss anything? What else should I consider to look at?
Last edited by McNugget6750; 03-27-2023 at 09:54 AM.
#16
Hi all,
I have a similar, if not the same issue. I have a 2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles.
My mechanic mentioned after service that my old oil has a strong gas smell. We also needed to replace the oil dipstick as it was very rusty and the steel strands already started separating in some places.
So, water vapor in the crank case and gas accumulation in the oil. No other symptoms at the moment. No smell, no roughness, runs smooth and powerful, no visible oil leaks.
The internet, the forum, and some of my colleagues say: check the PCV system first. So the crank case ventilation system - as this seems be be caused (hypothesis) by the accumulation of minimal blow-by during combustion. The blow-by can contain unburned gas as well as water vapor. If not extracted to the air intake manifold, it can cause overpressure in the crank case as well as the other symptoms described above.
My mechanic whom I trust strongly suggested to sell the car. My take on this is that any car I might buy as a replacement will be at least as much more expensive as any repair on this car can be and I already know this car and like it, too. So before I take the car to CarMax, I'd like to try a few things, beginning with the PCV system.
Going from simple and cheap and complex and expensive I would believe the following makes sense (up for debate):
Did I miss anything? What else should I consider to look at?
I have a similar, if not the same issue. I have a 2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles.
My mechanic mentioned after service that my old oil has a strong gas smell. We also needed to replace the oil dipstick as it was very rusty and the steel strands already started separating in some places.
So, water vapor in the crank case and gas accumulation in the oil. No other symptoms at the moment. No smell, no roughness, runs smooth and powerful, no visible oil leaks.
The internet, the forum, and some of my colleagues say: check the PCV system first. So the crank case ventilation system - as this seems be be caused (hypothesis) by the accumulation of minimal blow-by during combustion. The blow-by can contain unburned gas as well as water vapor. If not extracted to the air intake manifold, it can cause overpressure in the crank case as well as the other symptoms described above.
My mechanic whom I trust strongly suggested to sell the car. My take on this is that any car I might buy as a replacement will be at least as much more expensive as any repair on this car can be and I already know this car and like it, too. So before I take the car to CarMax, I'd like to try a few things, beginning with the PCV system.
Going from simple and cheap and complex and expensive I would believe the following makes sense (up for debate):
- check and replace the breather check-valve (where is this located and what is the part number?) - is this part 35 in the above image?
- check and replace the electrically actuated PCV valve (where is this located and what is the part number?) - does not seem to be in above image...
- check and replace the oil separator on the firewall side of the engine. Word has it that the high pressure fuel pump must be removed in order to get to it. (where is this located and what is the part number?) - also not in above image
- optionally, check, clean, and replace all breather hoses
Did I miss anything? What else should I consider to look at?
although it isn’t likely related to your issue I would check this hose. A lot of people are having them rot and crack. Mine was completely broken in half. I think it does return air from crank area to turbo idk what the hell it does tbh. This part was good quality.
Air Intake Turbo Tube, Turbochagrer Intake Pipe Hose for Mercedes-Benz W172 SLK200 SLK250, W204 C180 C200 C250, W212 E200 E250 E250 M271 Engine, 2710901629 2710901729 2710902029 2711801819 2710901929
https://www.amazon.com/dp/B087PTNHMF?ref_=cm_sw_r_apin_dp_96G05NRGKRZ9GVGV7Z NG
Last edited by chabbs93; 03-27-2023 at 10:16 AM.
#17
Junior Member
c250 cgi M271 crankcase breather
Noticed a few issues while changing the oil over the weekend. Oil deposits on the air intake hose, dipstick is showing some rust build up on the upper section of the wire, and some oil seepage around sensors and cylinder head cover. I suspect perhaps a blocked PCV causing over-pressurization of the crankcase. I have attached a couple of pictures showing the general location and a closeup of what I believe to be the Crankcase Ventilation or PCV valve. You can see what appears to be oil from this part on the air intake hose. I can't find any references to the component or its part number. Can anybody help?
2013 C250 162,250 miles
2013 C250 162,250 miles
#19
Junior Member
Hi all,
I have a similar, if not the same issue. I have a 2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles.
My mechanic mentioned after service that my old oil has a strong gas smell. We also needed to replace the oil dipstick as it was very rusty and the steel strands already started separating in some places.
So, water vapor in the crank case and gas accumulation in the oil. No other symptoms at the moment. No smell, no roughness, runs smooth and powerful, no visible oil leaks.
The internet, the forum, and some of my colleagues say: check the PCV system first. So the crank case ventilation system - as this seems be be caused (hypothesis) by the accumulation of minimal blow-by during combustion. The blow-by can contain unburned gas as well as water vapor. If not extracted to the air intake manifold, it can cause overpressure in the crank case as well as the other symptoms described above.
My mechanic whom I trust strongly suggested to sell the car. My take on this is that any car I might buy as a replacement will be at least as much more expensive as any repair on this car can be and I already know this car and like it, too. So before I take the car to CarMax, I'd like to try a few things, beginning with the PCV system.
Going from simple and cheap and complex and expensive I would believe the following makes sense (up for debate):
Did I miss anything? What else should I consider to look at?
I have a similar, if not the same issue. I have a 2012 Mercedes C250 1.8l Turbo with 150Kw at 89k miles.
My mechanic mentioned after service that my old oil has a strong gas smell. We also needed to replace the oil dipstick as it was very rusty and the steel strands already started separating in some places.
So, water vapor in the crank case and gas accumulation in the oil. No other symptoms at the moment. No smell, no roughness, runs smooth and powerful, no visible oil leaks.
The internet, the forum, and some of my colleagues say: check the PCV system first. So the crank case ventilation system - as this seems be be caused (hypothesis) by the accumulation of minimal blow-by during combustion. The blow-by can contain unburned gas as well as water vapor. If not extracted to the air intake manifold, it can cause overpressure in the crank case as well as the other symptoms described above.
My mechanic whom I trust strongly suggested to sell the car. My take on this is that any car I might buy as a replacement will be at least as much more expensive as any repair on this car can be and I already know this car and like it, too. So before I take the car to CarMax, I'd like to try a few things, beginning with the PCV system.
Going from simple and cheap and complex and expensive I would believe the following makes sense (up for debate):
- check and replace the breather check-valve (where is this located and what is the part number?) - is this part 35 in the above image?
- check and replace the electrically actuated PCV valve (where is this located and what is the part number?) - does not seem to be in above image...
- check and replace the oil separator on the firewall side of the engine. Word has it that the high pressure fuel pump must be removed in order to get to it. (where is this located and what is the part number?) - also not in above image
- optionally, check, clean, and replace all breather hoses
Did I miss anything? What else should I consider to look at?
#20
Senior Member
Not knowledgeable but this is what I did.
I replaced my crankcase vent valve, pictured on post#14 last week on my C250 2013. It's located under the intake manifold.
Look at post#17 picture on the right side the connector with red tabs, it connects to the crankcase vent valve. As far as the electric connector goes for it, I will send a photo when I get home, you can look in that area to see if anything came off or loose.
I replaced my crankcase vent valve, pictured on post#14 last week on my C250 2013. It's located under the intake manifold.
Look at post#17 picture on the right side the connector with red tabs, it connects to the crankcase vent valve. As far as the electric connector goes for it, I will send a photo when I get home, you can look in that area to see if anything came off or loose.
#21
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2012 Mercedes C250 1.8 Turbo
Sold the car sine it also gave me the check engine light in some cases when I was driving for multiple hours and then red-line overtake someone. All of a sudden I got a limb home. That repeated a few times. I'm very sad but I didn't want to deal with this engine anymore.
#22
Hi All,
Thought I would share my experience with this problem. I have been experiencing lots of positive crankcase ventilation when removing the oil cap when the engine is running as well as accumulation of oil in the intake manifold and inter cooler piping. My mechanic has also said that he found a significant amount of oil in the intake piping that connects to the turbo in post #17 (this will be my next problem to tackle).
On my 2011 facelift M271 engine, they had removed the piping mess that connected to the engine block. In place of it, they put a single oil separator/PCV. Now this part had failed and I found that there was an accumulation of oil/gas that was entering through this piping that connects to the intake manifold. I did a bit of research on the internet and found that some people in Russia had added an extra oil separator/PCV onto this piping to avoid any oil getting through and have had no issues with it so far (If anything, it’s an upgrade). Because it’s hard plastic, I trimmed the tubing and added a bit of bike tyre and hose clamp to secure the additional PCV in the middle. If I had the time, I would create an entirely new piece out of new parts with rubber hosing but this will do. So far no issues. I have been experiencing less positive crankcase ventilation so far.
Thought I would share my experience with this problem. I have been experiencing lots of positive crankcase ventilation when removing the oil cap when the engine is running as well as accumulation of oil in the intake manifold and inter cooler piping. My mechanic has also said that he found a significant amount of oil in the intake piping that connects to the turbo in post #17 (this will be my next problem to tackle).
On my 2011 facelift M271 engine, they had removed the piping mess that connected to the engine block. In place of it, they put a single oil separator/PCV. Now this part had failed and I found that there was an accumulation of oil/gas that was entering through this piping that connects to the intake manifold. I did a bit of research on the internet and found that some people in Russia had added an extra oil separator/PCV onto this piping to avoid any oil getting through and have had no issues with it so far (If anything, it’s an upgrade). Because it’s hard plastic, I trimmed the tubing and added a bit of bike tyre and hose clamp to secure the additional PCV in the middle. If I had the time, I would create an entirely new piece out of new parts with rubber hosing but this will do. So far no issues. I have been experiencing less positive crankcase ventilation so far.