Oil Leak from driver side onto Cats
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Junior Member
Joined: Aug 2022
Posts: 22
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From: West-Lafayette, IN / Skelleftea, Sweden
2015 Mercedes Benz C63 Edition 507
Oil Leak from driver side onto Cats
Hey everyone
I got a 2015 507 a month back and I finally got to doing the oil change (did the full kit from FCP Euro with Ceratec) in the process I noticed oil leaking from above onto cats and down onto the plastic panels underneath
It also smells like oil after I turn the car off and may smoke a little after I push it on a spirited drive
At idle it sometimes has a jerk that is bigger than normal V8 vibrations but nothing crazy
I m thinking it is either the valve cover gasket leaking onto the cats
I have been looking around and understood that it could be the PCV valve that is bad
Not sure
Did anyone have a similar issue?
I attached some pictures that I took when I did the oil change (sorry they aren't great)
I got a 2015 507 a month back and I finally got to doing the oil change (did the full kit from FCP Euro with Ceratec) in the process I noticed oil leaking from above onto cats and down onto the plastic panels underneath
It also smells like oil after I turn the car off and may smoke a little after I push it on a spirited drive
At idle it sometimes has a jerk that is bigger than normal V8 vibrations but nothing crazy
I m thinking it is either the valve cover gasket leaking onto the cats
I have been looking around and understood that it could be the PCV valve that is bad
Not sure
Did anyone have a similar issue?
I attached some pictures that I took when I did the oil change (sorry they aren't great)
Thread Starter
Junior Member
Joined: Aug 2022
Posts: 22
Likes: 8
From: West-Lafayette, IN / Skelleftea, Sweden
2015 Mercedes Benz C63 Edition 507
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Joined: May 2017
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From: West by god Virginia
'08 C300 4Matic Sport / '11 C63
Run your hand along the valve cover bottom lip and try to follow it. I and a couple others chased this down and it was actually the cam phaser housing gasket leaking and it trails and blows back following the valve cover and heads. Worth at least a double check.
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2020 C300
Thread Starter
Junior Member
Joined: Aug 2022
Posts: 22
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From: West-Lafayette, IN / Skelleftea, Sweden
2015 Mercedes Benz C63 Edition 507
Thanks a lot I will do that tonight and keep the updates coming
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Junior Member
Joined: Aug 2022
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From: West-Lafayette, IN / Skelleftea, Sweden
2015 Mercedes Benz C63 Edition 507
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12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
It is not your head gasket, head gaskets don't leak oil when they go they leak coolant and combustion pressure.
What it is for sure because every M156 with plastic valve covers leaks in the bottom corner of the drivers side and drips onto the cat. I have had 3 c63's and all have leaked in that same place. Normally a new set of valve cover gaskets solves it, I had one and several other people have also had a crack in the cover, also back bottom corner drivers side, they are hard to see unless you flex it a little when it is off to find the crack, but I learned the hard way after doing the gasket 2 times thinking I did something wrong or rolled it finally found the crack.
Drivers side is the harder one to do as a bit tighter but both are pretty easy and gaskets are like 40 bucks and you can do it in a few hours with the right set of torx bits and a few swivels and extensions (one bolt is tough to get to).
What it is for sure because every M156 with plastic valve covers leaks in the bottom corner of the drivers side and drips onto the cat. I have had 3 c63's and all have leaked in that same place. Normally a new set of valve cover gaskets solves it, I had one and several other people have also had a crack in the cover, also back bottom corner drivers side, they are hard to see unless you flex it a little when it is off to find the crack, but I learned the hard way after doing the gasket 2 times thinking I did something wrong or rolled it finally found the crack.
Drivers side is the harder one to do as a bit tighter but both are pretty easy and gaskets are like 40 bucks and you can do it in a few hours with the right set of torx bits and a few swivels and extensions (one bolt is tough to get to).
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2011 c63
Two options to solve your problem
1, valve cover gaskets but probably not the case
2, more likely cam adjuster seals in the front.
I had this same leak, replaced the valve cover gaskets and still had the leak. Went back in and replaced the cam adj seals and problem solved. The leak presents itself on the side of the engine below the exhaust manifold as the fan blow the oil back there.
Since you have to remove or lift valve covers to replace the cam adj seals just do both valve cover and cam adj seals at the same time. The seals are cheap so hope this helps you out.
1, valve cover gaskets but probably not the case
2, more likely cam adjuster seals in the front.
I had this same leak, replaced the valve cover gaskets and still had the leak. Went back in and replaced the cam adj seals and problem solved. The leak presents itself on the side of the engine below the exhaust manifold as the fan blow the oil back there.
Since you have to remove or lift valve covers to replace the cam adj seals just do both valve cover and cam adj seals at the same time. The seals are cheap so hope this helps you out.
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Joined: Mar 2019
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2011 c63
this is your issue, trust me
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Joined: Aug 2022
Posts: 22
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From: West-Lafayette, IN / Skelleftea, Sweden
2015 Mercedes Benz C63 Edition 507
Thanks a lot for all your comments and suggestions, I ran my hand and there was oil along the whole length of the valve cover, so I think I’ll change both valve cover and the cam one and hopefully that fixes it
ill keep it updated once I receive the parts
ill keep it updated once I receive the parts
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12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
Also just a note, the older aluminum valve covers (that leak much less often) use the same gasket on the perimeter as the newer plastic ones, but the donut gaskets around the spark plug holes are different, they are green on the aluminum covers and orange like the perimeter gasket on the plastic covers, so just make sure you get the right ones based on which covers you have. Also take a good look at the tips of your cams and the lifter buckets for wear so see how they look as they are common to have some wear and gives you a good idea of top end health and longevity.
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Joined: Jan 2018
Posts: 415
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From: Whitehouse Station, NJ
2012 C63 P31 Sedan
Two options to solve your problem
1, valve cover gaskets but probably not the case
2, more likely cam adjuster seals in the front.
I had this same leak, replaced the valve cover gaskets and still had the leak. Went back in and replaced the cam adj seals and problem solved. The leak presents itself on the side of the engine below the exhaust manifold as the fan blow the oil back there.
Since you have to remove or lift valve covers to replace the cam adj seals just do both valve cover and cam adj seals at the same time. The seals are cheap so hope this helps you out.
1, valve cover gaskets but probably not the case
2, more likely cam adjuster seals in the front.
I had this same leak, replaced the valve cover gaskets and still had the leak. Went back in and replaced the cam adj seals and problem solved. The leak presents itself on the side of the engine below the exhaust manifold as the fan blow the oil back there.
Since you have to remove or lift valve covers to replace the cam adj seals just do both valve cover and cam adj seals at the same time. The seals are cheap so hope this helps you out.
