S-Class (W221) 2007-2013: S 320 CDI, S 350, S 450, S 500, S 550, S 420 CDI, S 600

"Burning Oil"

Old Mar 29, 2012 | 01:26 AM
  #1  
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S550 4MATIC W221, W222, Lotus Elise
"Burning Oil"

My car had “burning oil” issue recently. In 3-4 month, the oil level goes from max to almost min. Looked everywhere there is no sign of oil leak, not on the engine, not on the under tray. Topping off oil but same thing again. Other than that, the car performs as well as it should be so that I did not make a big of it.

One day, I found out that a plastic cap (camshaft cover) on top of the engine is a little oily around it. Hmm, could that be it? Sure it is. I can even rotate the cap easily by hand. Because of small amount leak, oil vaporized by the engine heat so that I was never found the cause.

Called dealer parts and caps cost only $4-$5 apiece. Parts guy knew what I was talking about right away and said they have plenty of them in stock. Parts have been 3-4 revisions already. MB does use low quality parts.

I replaced all three of them, although only one shown oily.

Issue resolved by a simple fix.

If your S550 developed abnormal oil consumptions, check that out first before go into cylinder pressure tests and other expensive route J

Last edited by mb1000; Mar 29, 2012 at 05:58 AM.
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Old Mar 29, 2012 | 04:08 AM
  #2  
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c350
Originally Posted by mb1000
My car had “burning oil” issue recently. In 3-4 month, the oil level goes from max to almost min. Looked everywhere there is no sign of oil leak, not on the engine, not on the under tray. Topping off oil but same thing again. Other than that, the car performs as well as it should be so that I did not make a big of it.

One day, I found out that a plastic cap (camshaft cover) on top of the engine is a little oily around it. Hmm, could that be it? Sure it is. I can even rotate the cap easily by hand. Because of small amount leak, oil vaporized by the engine heat so that I was never found the cause.

Called dealer parts and caps cost only $4-$5 apiece. Parts guy knew what I was talking about right away and said they have plenty of them in stock. Parts have been 3-4 revisions already.

I replaced all three of them, although only one shown oily.

Issue resolved by a simple fix.

If your S550 developed abnormal oil consumptions, check that out first before go into cylinder pressure tests and other expensive route J
Thanks for the heads up. I need to replace one on mine too.
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Old Mar 29, 2012 | 06:22 AM
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2015 s550v4
Thanks! Can you post a picture of the cap you are talking about? Mine uses more oil than I think it should, and would like to check this ...
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Old Mar 29, 2012 | 06:23 AM
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S550 4MATIC W221, W222, Lotus Elise
Originally Posted by mnatl
Thanks for the heads up. I need to replace one on mine too.
NP. Some tabs on the cap already broken and missing when I took it out. Also, make sure to install caps flush with the engine. Otherwise, it may cause more oil leak.

MB does use some low quality parts, e.g. idle pulley, engine mounts, etc.
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Old Mar 31, 2012 | 06:59 AM
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Mb1000 - what is part number you found? Thanks
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Old Apr 1, 2012 | 10:27 PM
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S550 4MATIC W221, W222, Lotus Elise
Originally Posted by new550
Mb1000 - what is part number you found? Thanks
I was out of town and just came back. Part #:

2x A 000 998 55 90
1x A 000 998 56 90

See image for ref.
Attached Thumbnails "Burning Oil"-untitled.bmp  
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Old Apr 6, 2012 | 09:06 AM
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Thanks for posting this, I swapped my dad' Fleet wood with a metal one too.Good to see it was an easy and cheap fix
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