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I've got a 2010 ML63 AMG which has been blue smoking on start up and also after hard braking. After reading about pcv valve failures I decided to replace the valve and give the intake a clean at the same time. The valve diaphragm was split so I was sure this was the fault. At first there seemed to be a big improvement but after only a few miles of driving it was back smoking as before. I've removed the intake and pcv again and inspected them.
The pcv seems to be fine it is a brand new one from Mercedes. However the rear of the intake is coated in oil to the extent it is pooling behind the rear throttle body. The car is using about 1 litre of oil every 100 miles or so. Also the exhaust tips are getting coated in what must be oil residue on any long journeys.
The most noticeable smoke appears when you coast to a stop and then pull off. Also when the car is warm and gets re started after a few minutes of standing. It also smokes very bad on hard acceleration.
It almost seems like the pcv if feeding oil straight into the intake.
I think the previous owner may have mapped the car but I'm not 100 percent sure on this.
I've taken a few pictures to show the extent of the oil.
I’m having a similar issue with my ‘08 ML63, but mine happened after I replaced the PCV.
Bought it last September with 100k on the odometer, so I immediately tore into it replacing the original head bolts, noisy VVT intake gear, injectors, coils (#8 was going open circuit when hot), magnesium throttle body mid-plate with the aftermarket aluminum one, and a new Mercedes PCV…
Intake was oil free for the most part on the inside when I took it apart in September. Since getting it back together it has consumed over 2 gallons of oil in the past 3500 miles!!!
I haven’t had time till now to really look into where all the oil has been going. No external leaks…. Was suspecting the PCV, and trying to baby it getting to work and back so I don’t completely plug the cats with oil. I get huge smoke clouds under hard acceleration, but nothing at startup, and can’t see any smoke under normal cruising conditions...
I found a bunch of oil in the lower intake half (below the throttle body’s) so I’m sure the upper half is stuffed full…
Does anyone know how much vacuum the PCV is supposed to pull on the crankcase?
Engine started making a squealing sound during high idle cold starts about a month after getting it back together….
I think we both may have installed brand new ‘defective’ Mercedes PCV valves…???
Plan on tearing into mine tonight and replacing the PCV valve with a new one again… Have a catch can coming for it too….
I’ll see if I can get a vacuum reading at the dipstick tube, before and after….
Last edited by jeremyf1; Jun 21, 2021 at 02:15 PM.
Ok, perhaps I should have started my own thread on this, but since it has been a couple months since the OP posted his excessive PCV oil problem, much like mine, I won’t be holding my breath on any responses.
Déjà vu from my requests for help in the ML55 ML63 AMG sub-forum….. That part of of MBWorld sure is dead. Ha ha
At any rate, I checked the vacuum at the dipstick tube last night. A fluctuating 1 in/hg. So… That shoots down my thoughts of a defective PCV valve…
Searching the net last night to try and figure out the passageway of flow for the PCV, I see it follows the block gallery up to the front cover, passes through that into a rubber tube, then back to the cover in front of the timing chain idler gear…
I did remove the oil filter assembly (new gasket of course), and I do remember one of the bolts requiring sealer, but don’t remember which bolt, or what the sealer was sealing off (oil or coolant?).
Could it be that easy? Try and re-seal the bolt? Unlikely… Lol. I guess the RTV between block and front cover may have been compromised by removing the upper filter housing bolt too. That’s the bolt directly above the PCV passageway.
Still a bit strange that prior to me doing any preventative maintenance, the intake had nothing more than a light oil film. It’s so full of oil now it’s dripping through the throttle body’s to the lower intake half. This definitely isn’t a ‘misting’ problem that can be alleviated by a catch can. I’d have to be draining the damn thing daily, or find a 5 gallon one I can mount in the trunk. Lol
Worth mentioning. I did put about 500 miles on the ML while waiting for my parts to arrive last year, and it definitely wasn’t blowing a massive smoke cloud then, but it sure as hell has been shortly afterwards my so called, ‘preventative maintenance’. ☹️
To get me by for the time being, I blocked off the vacuum line to the intake runner vacuum servo so it can’t switch over from the short runner length. Took it for a short trip to the store last night. It felt a bit rich at lower RPM’s, but at least it wasn’t sucking up oil from the bottom of the upper half, and blowing the MASSIVE smoke cloud… That has been soooo embarrassing!!!! 🥴
Up till now I’ve gotten by with the kindness of others posting the WIS files on here for the intake and head bolt replacements (many thanks to all those that have posted the needed WIS files here), but looks like **** has officially hit the fan, and I might have to make a quick ‘non-educated’ guess on a STAR clone. Been wanting one to setup my new black surround headlights I bought (refuse to go back to my MB dealer for that), and most importantly now, I clearly need the included WIS and EPC to help and find all the parts I need that are not on the online MB vendors parts diagrams… The list for those parts have seriously grown now….
Any M156 gurus here that can tell me exactly what I’m looking at in these last two photos?
Is that round collar covering up the timing chain idler gear in second to last pict just a ‘splash shield’?
And the last pict. Is that a seal the idler shaft goes into, or is that a bearing?
If it’s not the filter housing bolt that requires better sealing, or compromised RTV where the PCV passes through block to cover, then the oil must be coming from that front cover timing chain idler shaft area…???
Thanks in advance,
Jeremy.
Last edited by jeremyf1; Jun 23, 2021 at 12:32 AM.
After watching this rebuild video series below, I decided removing the front cover is going to be my absolute last option. Front cover is literally the last thing to come off prior to removing the crankshaft main bearing girdle…
Good M156 rebuild video, if you have a few hours to kill…
I went ahead and bought a new MB PCV again, even though the last one seemed to be fine, and found this inside intake…
This was not the RMT throttle body plate, but a different one off eBay with nothing but 5 star reviews, and a slightly lower price..
Unbelievable!!!! Who decided using a non-petroleum compatible rubber inside a intake was a good cost savings idea…???
A lot of the gasket was missing, and consumed by #8 cylinder. Bits of rubber gasket was actually stuck and had bridged the insulator/ground strap on the #8 plug…
Plugs were brand new looking just 3500 miles ago, and had no deposits on them, or oil on the threads….
#7 looked a bit better, but obviously had been consuming oil and rubber too…
The rest of the plugs looked decent….
Re-installed the 14 year old original MB throttle body gasket, which was still perfectly fine, new PCV, and because I doubted the PCV was defective, a catch can…
600 miles later…. No more smoke on hard acceleration, and not even a drop of oil in the catch can…😎
Wish I had a definitive answer to the oil in the intake, but I’m blaming it on the crappy rubber gasket gumming up the rings, creating excessive blow-by. I noticed no difference in the crankcase vacuum with new PCV…
Soooo, for anyone that bought, or is looking to buy one of those cheap eBay throttle body plates, DO NOT use the new rubber gasket supplied. You’ve been warned. Ha ha. I never would have expected this….
Do yourself a favor and re-use the old MB gasket….
Contacting the eBay seller to see if they recently changed their supplier, or were aware of the issue, only resulted in a generic ‘copy/paste’ reply of their warranty process…
So much for trying to save a few $… IDK if the RMT gasket is any better, but can only assume it is...
I've got a 2010 ML63 AMG which has been blue smoking on start up and also after hard braking. After reading about pcv valve failures I decided to replace the valve and give the intake a clean at the same time. The valve diaphragm was split so I was sure this was the fault. At first there seemed to be a big improvement but after only a few miles of driving it was back smoking as before. I've removed the intake and pcv again and inspected them.
The pcv seems to be fine it is a brand new one from Mercedes. However the rear of the intake is coated in oil to the extent it is pooling behind the rear throttle body. The car is using about 1 litre of oil every 100 miles or so. Also the exhaust tips are getting coated in what must be oil residue on any long journeys.
The most noticeable smoke appears when you coast to a stop and then pull off. Also when the car is warm and gets re started after a few minutes of standing. It also smokes very bad on hard acceleration.
It almost seems like the pcv if feeding oil straight into the intake.
I think the previous owner may have mapped the car but I'm not 100 percent sure on this.
I've taken a few pictures to show the extent of the oil.
hi, did you manage to resolve your issue? I’m having a similar thing on my 204 c63
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