SL55/63/65/R230 AMG: Head Gasket Oil Leak??
Thread Starter
Senior Member
Joined: Mar 2021
Posts: 274
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From: Rocky Mountains, Colorado
Just sold my '11 Porsche TurboS cab for an '03 SL55!
Head Gasket Oil Leak??
I've been chasing a motor oil leak around the rear of the left cylinder bank. I jumped to the conclusion that it was the valve cover gasket, but when I got the covers off, they looked pretty dry. New gaskets anyway, but the leak is still there. After cleaning and driving and cleaning and driving it sure looks like its the head gasket that appears to have some RTV like black rubber sealant around the lower edge. I've checked and rechecked the breather hoses under and around the throttle body and they're dry too. I don't see any other potential source up in that area.
Anyone experience this leak? Are there other leak sources I should be looking at? Seems a bit odd on a 73k mile car, but it is 18 years old...…..
Thanks for any help.
Anyone experience this leak? Are there other leak sources I should be looking at? Seems a bit odd on a 73k mile car, but it is 18 years old...…..
Thanks for any help.
MBWorld Fanatic!
Joined: May 2009
Posts: 1,187
Likes: 239
From: Santa Clara, Ca
2003 SL55 / 2002 SLK32
I've been chasing a motor oil leak around the rear of the left cylinder bank. I jumped to the conclusion that it was the valve cover gasket, but when I got the covers off, they looked pretty dry. New gaskets anyway, but the leak is still there. After cleaning and driving and cleaning and driving it sure looks like its the head gasket that appears to have some RTV like black rubber sealant around the lower edge. I've checked and rechecked the breather hoses under and around the throttle body and they're dry too. I don't see any other potential source up in that area.
Anyone experience this leak? Are there other leak sources I should be looking at? Seems a bit odd on a 73k mile car, but it is 18 years old...…..
Thanks for any help.
Anyone experience this leak? Are there other leak sources I should be looking at? Seems a bit odd on a 73k mile car, but it is 18 years old...…..
Thanks for any help.
See pic
hope that helps,
Chris
Last edited by latemodel21; Jun 28, 2021 at 10:41 AM.
Thread Starter
Senior Member
Joined: Mar 2021
Posts: 274
Likes: 22
From: Rocky Mountains, Colorado
Just sold my '11 Porsche TurboS cab for an '03 SL55!
Chris…….YES, very helpful.
Can you tell me the source of this leak from under the Supercharger?
What will I need to remove and what seals/gaskets/hoses etc. will I need to reseal and reassemble things?
Thanks a lot.
MK19
Can you tell me the source of this leak from under the Supercharger?
What will I need to remove and what seals/gaskets/hoses etc. will I need to reseal and reassemble things?
Thanks a lot.
MK19
MBWorld Fanatic!
Joined: May 2009
Posts: 1,187
Likes: 239
From: Santa Clara, Ca
2003 SL55 / 2002 SLK32
Supercharge front-case-oil could I suppose (but doubt there would be much).
Coolant the from Intercooler and/or supply pipes could make its way here.
A really bad valve cover leak perhaps (but you have ruled that out already).
And, I guess you could have a bad seal on the retainer-plate (of the rear-main seal) ... but that seems like a long-shot (and requires the trans be separated from the engine to get at ... so lets hope not)
Hopefully someone else will have some experience that they can share that would shed some light here.
but first, do confirm that this "drain" is the source of your drip
Chris
Last edited by latemodel21; Jun 28, 2021 at 10:59 AM.
Thread Starter
Senior Member
Joined: Mar 2021
Posts: 274
Likes: 22
From: Rocky Mountains, Colorado
Just sold my '11 Porsche TurboS cab for an '03 SL55!
Thanks for the picture and all of your inputs here Chris.....and yes, hoping for further insights from others too.
I'm now wondering how I'll confirm (or not) the leakage you have pointed to. In the photo, am I looking at the rear of the main (crank) shaft with the motor removed? Or is that the front of the blower with the clutch removed?
I'm pretty sure it's not the main shaft seal as I can inspect the lower/inside of the bell housing and it's pretty dry.
I am seeing only motor oil, no antifreeze. And no oil in the coolant tank either.
It's a reasonably sizable leak that can result in a 6" diameter oil spot after a drive and cool down.
I'm guessing that the main oiling system also lubricates the blower......correct??
Best, Mike
I'm now wondering how I'll confirm (or not) the leakage you have pointed to. In the photo, am I looking at the rear of the main (crank) shaft with the motor removed? Or is that the front of the blower with the clutch removed?
I'm pretty sure it's not the main shaft seal as I can inspect the lower/inside of the bell housing and it's pretty dry.
I am seeing only motor oil, no antifreeze. And no oil in the coolant tank either.
It's a reasonably sizable leak that can result in a 6" diameter oil spot after a drive and cool down.
I'm guessing that the main oiling system also lubricates the blower......correct??
Best, Mike
MBWorld Fanatic!
Joined: May 2009
Posts: 1,187
Likes: 239
From: Santa Clara, Ca
2003 SL55 / 2002 SLK32
Thanks for the picture and all of your inputs here Chris.....and yes, hoping for further insights from others too.
I'm now wondering how I'll confirm (or not) the leakage you have pointed to. In the photo, am I looking at the rear of the main (crank) shaft with the motor removed? Or is that the front of the blower with the clutch removed?
I'm pretty sure it's not the main shaft seal as I can inspect the lower/inside of the bell housing and it's pretty dry.
I am seeing only motor oil, no antifreeze. And no oil in the coolant tank either.
It's a reasonably sizable leak that can result in a 6" diameter oil spot after a drive and cool down.
I'm guessing that the main oiling system also lubricates the blower......correct??
Best, Mike
I'm now wondering how I'll confirm (or not) the leakage you have pointed to. In the photo, am I looking at the rear of the main (crank) shaft with the motor removed? Or is that the front of the blower with the clutch removed?
I'm pretty sure it's not the main shaft seal as I can inspect the lower/inside of the bell housing and it's pretty dry.
I am seeing only motor oil, no antifreeze. And no oil in the coolant tank either.
It's a reasonably sizable leak that can result in a 6" diameter oil spot after a drive and cool down.
I'm guessing that the main oiling system also lubricates the blower......correct??
Best, Mike
the blower is not connected to the main oiling system, but instead has a smallish gearbox in the front that holds a small amount of fluid (probably not the source of your re-occurring spot).
HTH,
Chris
Last edited by latemodel21; Jun 28, 2021 at 01:52 PM.
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Thread Starter
Senior Member
Joined: Mar 2021
Posts: 274
Likes: 22
From: Rocky Mountains, Colorado
Just sold my '11 Porsche TurboS cab for an '03 SL55!
Embarrassing!!
I never found the hole/vent that you pointed out latemodel21, I probably needed a mirror that I didn't have at hand but I did find the source of my main oil leak.
Looking around up under the head/valve I sensed that maybe the newly replaced valve cover gasket could be to blame even though I had previously had the coils out and could run my fingers all around the suspect rear/lower part of the gasket and they came up more or less dead dry.
But I decided to pull the valve cover in case I didn't get a part of the gasket in the groove. Well, the gasket was in the groove nicely and looked great. But as I was trying to sight down behind the head for any clue, I spotted the mounting tab for a vacuum line that is intended to be attached at the upper, rear most valve cover bolt. It was sitting right on the gasket surface of the head. You can probably guess the rest. I closely reexamined the valve cover gasket in that location and found a matching impression. Yep, rookie move, I'd not noticed this mounting tab and I slid the valve cover right back in there and right on top of this mounting bracket. It's surprising that it sealed as well as it did. All better now except for a very minor leak more forward on the engine that I'll go after next.
The other observation here is that these Syn oils tend to be dry in a film state as was the case here......so it can be hard to detect the leak source. I guess that's why some shops use dye/black lights.
Thanks all for the help and especially Chris. Cheers!!
Looking around up under the head/valve I sensed that maybe the newly replaced valve cover gasket could be to blame even though I had previously had the coils out and could run my fingers all around the suspect rear/lower part of the gasket and they came up more or less dead dry.
But I decided to pull the valve cover in case I didn't get a part of the gasket in the groove. Well, the gasket was in the groove nicely and looked great. But as I was trying to sight down behind the head for any clue, I spotted the mounting tab for a vacuum line that is intended to be attached at the upper, rear most valve cover bolt. It was sitting right on the gasket surface of the head. You can probably guess the rest. I closely reexamined the valve cover gasket in that location and found a matching impression. Yep, rookie move, I'd not noticed this mounting tab and I slid the valve cover right back in there and right on top of this mounting bracket. It's surprising that it sealed as well as it did. All better now except for a very minor leak more forward on the engine that I'll go after next.
The other observation here is that these Syn oils tend to be dry in a film state as was the case here......so it can be hard to detect the leak source. I guess that's why some shops use dye/black lights.
Thanks all for the help and especially Chris. Cheers!!
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MBWorld Fanatic!
Joined: May 2009
Posts: 1,187
Likes: 239
From: Santa Clara, Ca
2003 SL55 / 2002 SLK32
I never found the hole/vent that you pointed out latemodel21, I probably needed a mirror that I didn't have at hand but I did find the source of my main oil leak.
Looking around up under the head/valve I sensed that maybe the newly replaced valve cover gasket could be to blame even though I had previously had the coils out and could run my fingers all around the suspect rear/lower part of the gasket and they came up more or less dead dry.
But I decided to pull the valve cover in case I didn't get a part of the gasket in the groove. Well, the gasket was in the groove nicely and looked great. But as I was trying to sight down behind the head for any clue, I spotted the mounting tab for a vacuum line that is intended to be attached at the upper, rear most valve cover bolt. It was sitting right on the gasket surface of the head. You can probably guess the rest. I closely reexamined the valve cover gasket in that location and found a matching impression. Yep, rookie move, I'd not noticed this mounting tab and I slid the valve cover right back in there and right on top of this mounting bracket. It's surprising that it sealed as well as it did. All better now except for a very minor leak more forward on the engine that I'll go after next.
The other observation here is that these Syn oils tend to be dry in a film state as was the case here......so it can be hard to detect the leak source. I guess that's why some shops use dye/black lights.
Thanks all for the help and especially Chris. Cheers!!
Looking around up under the head/valve I sensed that maybe the newly replaced valve cover gasket could be to blame even though I had previously had the coils out and could run my fingers all around the suspect rear/lower part of the gasket and they came up more or less dead dry.
But I decided to pull the valve cover in case I didn't get a part of the gasket in the groove. Well, the gasket was in the groove nicely and looked great. But as I was trying to sight down behind the head for any clue, I spotted the mounting tab for a vacuum line that is intended to be attached at the upper, rear most valve cover bolt. It was sitting right on the gasket surface of the head. You can probably guess the rest. I closely reexamined the valve cover gasket in that location and found a matching impression. Yep, rookie move, I'd not noticed this mounting tab and I slid the valve cover right back in there and right on top of this mounting bracket. It's surprising that it sealed as well as it did. All better now except for a very minor leak more forward on the engine that I'll go after next.
The other observation here is that these Syn oils tend to be dry in a film state as was the case here......so it can be hard to detect the leak source. I guess that's why some shops use dye/black lights.
Thanks all for the help and especially Chris. Cheers!!
Cheers and happy holidays!
Chris
