2012 GL350 - Oil Disappearing- Crankcase Vent Valve?
 

My 2012 GL350 has started going through about 1 qt of oil every 300 miles. I replaced the oil cooler seals and timing chain a few thousand miles ago, and currently have no visible oil leaks. THe paper towel blowby test on the oil filler cap does not suggest blowby being an issue. I am wondering if the Crankcase Vent Valve could be bad, but not sure what to check to see if that is the culprit.

A few added notes: Engine is at 130K miles. Oil changed with proper MB spec since I have owned it. My check engine light is coming on and scanning shows an error of aborted regen. I've heard that excessive oil passing into the system could cause this, but not sure. I was also getting limited starts related to the DPF, but traced that to a faulty rear NOX sensor. I replaced the NOX sensor and no longer get kicked into the limited start, but can't get the check engine light and aborted regen errors to stay off (If I reset they come back within 50 miles). I am also wondering if the check engine and regen issues could be related to not getting the NOX sensor properly adapted?

Any suggestions on where to start looking would be appreciated. My main initial concern is to repair the oil issue before I clog the DPF.

Check turbo shaft for play. You are clogging the dpf and back pressure is blowing the seals of the turbo and oil is seeping through

You need star/ das to force a regen and go for a long ride that will let it finish.

Thanks for your response!

Ok, that makes sense. I do have DAS with developer mode, but I don't see where I can force the regen. The only option I see tells me it will happen automatically on next trip. I have tried that, but does not seem to complete. Is there a different way to force the regen? I've searched but can't find explicit instructions on it.

I do hear a hissing under the hood at times, so I believe you are probably correct about the pressure. Unfortunately I am still learning about my turbo diesel and am not quite sure where to start troubleshooting. I was so thrilled when I successfully replaced the oil seals and timing chain. It was great for a few months then this high oil consumption started.

I'll check the turbo shaft. If loose I presume that means a new turbo? Also, you don't think there is any need to look further into the Crankcase vent valve?

Any looseness (using a finger to push/pull) radially is a strong indication the front bearing is bad. Axial (along the shaft) movement is OK and usually doean't cause any problems. There is no way to check the rear bearing without removing the turbo (and if you do that you might as well replace /rebuild it anyway).

OK, been busy the last week but finally had some time to play with this.

Did a force regen via DAS special functions and went for about an hour drive. Progress bar only went about half way and never any further. I drove most of the time about 70 MPH, and exhaust temps were hovering around upper 300s to mid 400s (with some higher, some lower). Is this normal? The only time I was able to get the temps higher than 400 or so was during acceleration (which obviously I can't keep going much past 70 without getting a ticket). I had to self abort after an hour as I had an appointment, but it seems like something is causing the process to stick mid-way. Any ideas?

The turbo shaft does not seem to have any play. I did now; however, notice oil forming on the top of the engine cover on the passenger side. There is no oil residue on the hood itself, just on the top side of the engine cover. I will have more time tonight to inspect, but wondering if anyone has any suggestions to check? EGR Valve? Crankcase Valve?

To recap: while driving I do occasionally hear a hissing/swishing sound that seems to be related to the power steering or turbo. Unfortunately I cannot inspect while I am driving so all I currently have to go by is the oil residue on the top of the plastic engine cover and regen not being able to complete.

OK, I revisited the turbo inspection and I do indeed have play in the shaft. Looks like I will be ordering a new cartridge and doing a rebuild. Could this alone be what is causing the regen from completing?

DPF cleaner via turbo connection?
 

So my new turbo cartridge arrived today and I was thinking I should probably clean the DPF at the same time. Is there any reason why (when the turbo is removed) I couldn't just spray the LubriMoly DPF cleaner directly into the exhaust where the turbo usually connects? I am thinking this would be easier and better access than the standard approach to access via a side port.

Any reason I should not do it this way?

OK, so I am getting ready to replace the turbo cartridge, and am seeing the strangest oil spot on the top of my engine cover (see attached photo). The weird thing is that there is no oil on the underside of the hood (directly above this spot) and there does not appear to be oil on the underside of the cover, so where is it coming from? Just wondering if I should be looking at anything else while the turbo is off?
https://cimg2.ibsrv.net/gimg/www.mbw...2d217ba056.jpg

CCRobin,

I have a 2011 GL350 that I have meticulously maintained since 21k miles when I got it back in 2012. It has never gone more than 5k miles on an oil change and has never used a drop between changes until a month ago! All of a sudden it started to use a quart per 700 miles so I ceased driving it right away as I was worried about the DPF. I know have 146k miles so I started thinking about where the oil could be going, no leaks engine is spotless and garage floor is also. Took intake off to look at the turbo, real oily but no play in the turbo at all in any direction. Everything in the turbo looked spotless also.

I have read about the earlier versions of the OM642 crankcase breather (the one that mounted on top of the valve cover) failing internally. Got to studying the crank case breather on my year and it uses a breather valve on the back of the head on the passenger side, it essentially slips over the camshaft end where the centrifugal de-mister is on the cam and pulls vapor theoretically through the hollow of the cam. The breather valve seal where it seals around the cam was rock hard and I questioned if it was sealing well. I disassembled the valve and the diaphram inside was not torn but it was very stiff. So anyway I replaced the valve and hope to see if this helps any. Only thing I can guess next is a turbo ring seal. My engine has no blowby at the oil cap.

Cost of the new CrankCase breather valve was $158.00.

Here is a pic of the new and the old....http://www.peachparts.com/shopforum/...on-solved.html

Regen of a partially clogged dpf will take a long time. No need to do 70 mph to keep it going. You can dump the dpf cleaner downstream on the exhaust side without Ill effects. It might help. If it doesn’t work a mechanical cleaning of the dpf might be on order. Longitudinal play of turbo shaft is ok. Radial is not. Let us know.

Well, the turbo rebuild went well. I can sure tell a difference. The engine sounds smoother and there is noticable difference in throttle response. Looking at the old turbo I found a few slightly damaged blades on the exhaust side, so it definitely needed to be replaced. For $110 and 6 hours work it was well worth it.

Unfortunately the DPF cleaner did not arrive yet, and I could not go without the car today so I will have to add that via the probe opening. I have a 2 hour drive today so I'll force a regen and see if I have better luck now that the turbo is healthy.

So I performed a forced regen which finally completed successfully. My MIL returned; however, and fault code 13AF00 soot content too high error is still present.

I checked the actual values area of DAS and it shows Ash Content at 0, but Load State value is 15 (should be less than 9). All other values for the DPF are good. Should I do another force regen, or is there something else I should be looking at? I'm not finding any reference to what this "Load State" means.

For anyone that may be following, I did try another regen, and no improvement. The Load State remained at 15.

When I got home I added the Lubri Moly DPF cleaner that had been delivered today. It was very easy. I was able to reach up from under the passenger side of the vehicle, remove the temp probe with a crescent wrench, and sprayed in the cleaner with a simple $12 hudson sprayer. I added the first bottle and waited 30 minutes, then I added the 2nd bottle and waited another 30 minutes. I then re-assembled everything and started the engine. I put on the parking brake, placed the vehicle in neutral, and revved the engine at 2500 RPM for about 20 minutes. After about 1 minute I started getting a plume of grey smoke from the tailpipe. This continued for about 15 minutes. After this, I did a manual regeneration via DAS and went for a 40 minute drive. Regen did complete successfully, and once done the load state had been reduced to 6 (needs to be 9 or lower). This was a fairly significant reduction, and got me back into the safe zone. I was hoping to get final numbers below 5 - but I'll take a 6. Perhaps I'll do another treatment with the DPF cleaner. My sprayer did not have the proper angle to aim directly at the surface of the DPF cleaner, so I think another treatment with the proper spray angle will provide better results. At any rate - it appears the MIL is now off.

I have a 400 mile round trip to make this weekend, so I will hopefully see an improvement in MPG, and also will hopefully not use any oil on the trip.

I will post my results after the weekend and/or if I do a 2nd treatment of the DPF cleaner.

Sounds like overall you made some progress. I will be really curious as to if you see any oil consumption on your trip.

Also where did you get the turbo rebuild cassette? If this was your first time pulling the turbo how long did it take you?

Thanks for keeping your post updated!

I bought the turbo cartridge on Ebay. PM me if you want the actual listing/seller.

In all, the cartridge replacement took about 6 hours (though about 2 hours was killed with stripped screw heads I had to drill out and go to NAPA to get replacements). Basic tools only needed. E10 and E12 sockets, 10MM socket, 8mm and 10mm open end wrenches, and a T25 driver was about it.

Load state of 6 is just borderline. You can repeat the dpf procedure, but ... I would leave it alone for now.

Thanks. Yeah I figured I would check again in a few weeks and see where it is at.

ccrobin this is an example of a good thread. You stayed on it start to finish. I don't have a diesel but I'll thank you for it anyway.

Well, my check engine light is back on. I am also smelling some very hot exhaust type smell from the engine area. It seems to be running fine, so I'm not sure if the DPF cleaner just smells for a while (maybe still some in the system being burnt off), or perhaps I didn't get one of the exhaust flanges tight?

I did notice when I performed the manual regeneration that it completed successfully, but then seemed to start another regen cycle almost immediately. It seems as though it is constantly trying to regen. Anyone with an idea why that would be or what I should look for?

This is normal. Just drive and let it do it’s thing.

Update on oil consumption? Did the turbo swap out do the trick? How many miles did you do this weekend?
I did 240 miles on mine over the weekend and it appears to sipped some oil despite my crankcase breather valve replacement. Going to watch it for a week or so but the turbo is the only thing I can think of I have left. There is no way I am burning it via the rings or valves...

Ugh, just finished a 200 Mile drive and I'm pretty sure the new cartridge in my turbo has a bad bearing. Its whining/growling something fierce and when I got home and popped the hood there is smoke coming out from the area of the turbo. I gotta let it cool to see but I'm afraid I will find the shaft even more loose than on the one I just replaced.

a doa cartridge especially if you bought a chinese one can happen... you sure you dont have an exhaust leak? sometimes they "sing" just like a bad turbo

Well, considering I was seeing smoke coming from the area with the engine idling it could be an exhaust leak I suppose. Hoping to check it out more thoroughly this evening.

Sitting at my desk at work I think I know what the problem could be. When I re-assembled the turbo assembly I did not have new metal gaskets. While re-using the original metal gaskets was probably fine, I thought I'd be smart and also add some Permatex Ultra High Temp Exhaust Sealant. Well, I never stopped to think that "Ultra High Temp" is a relative term. I think the permatex is rated up to 700 degrees F. I'll bet the turbo goes upward of 1200 F.

I probably boiled the permatex right out of there on my 2 hour drive and started sucking air!

I'll post my findings once I know.