Tri1968

I have a 2007, clk550 carb, with 64k, recently I smell oil burn and see leak under the car. I bring to my friend mechanic. He diagnose camshaft gasket leak and need to be replace, is there such thing as camshaft gasket? Or I need is the valve cover gasket? Can someone with me some advice

Klinh

No, it valve covers leak and drop onto the exhaust and you get that oil burn smell.

Rudeney

Actually, a common leak (as I found out two weeks ago) is a leaky "cam plug". There are two of them on the back of the engine's left side valve cover. They are round plastic caps that snap in place on the ends of the valve cover right behind the cam shafts. There is a larger one, about 2 inches in diameter, behind the intake cam, and a smaller about one inch in diameter, behind the exhaust cam. You can barely see them between the valve cover and the firewall. You can feel them with your hand, though. Remove the engine covers and run your hand down there and if it comes back oily, that's the culprit. The good news is they are inexpensive and easy to replace. I paid about $14 for both of them and it took five minutes to replace them. Just use a plastic wedge (or a gentle hand with a screwdriver) to pry them loose, then snap the new ones in place.

kbahl21

yup i just got that fixed too. its called a camshaft housing plug or something

Tri1968

Thank Rudeney, I got it fix over the weekend. You are right, just pull out the cover and it's a 5min fix!

Black_CLK

yup its a cam plug got mines fixed not too long ago

Clkboi

Do you guys have a part number for this? Or a picture. I think i have the same problem and its driving me crazy!

Rudeney

This diagram will show you where it is. Dealer price shoudl be under $20 for the pair

nundad

I now have that problem and the dealer wants to charge me $450 to fix it. Are the plugs located at the back of the engine?

Clkboi

HOLY **** 450??

Apparently its very easy to DIY and parts are pretty cheap

nundad

Is the diagram the same for an 08 cls550?

Rudeney

Uh, that is beyond ridiculous! If it truly is just the cam plugs, then ask them if the job comes with a "happy ending", too! Yes, the cam plugs are on the rear left (US driver's) side of the engine. On the V8, you won't be able to see them without a mirror, but you will be able to feel them. You'll need to remove the engine cover for access. It literally takes 10 minutes to replace these, and no tools other than a screwdriver to pry the old ones off. They just snap in place.

Yidney

No way even a dealer is charging you $450 for that. They are talking about something else. It's about as hard as screwing the lid on a pickle jar. They are on the back of your heads. Use a small mirror.

nundad

Thanks. i'll check it out this weekend to see if I can change them out.

Glyn M Ruck

https://mbworld.org/forums/c-class-w...ngine-bay.html

nundad

Thanks for the photo Glyn. Now I know what to look for. I ordered two Cam plugs but they look like they are made of metal. Is the rubber I see on the phots a cap for the plugs?

Glyn M Ruck

The cam blankers are hard rubber.

nundad

Thanks

Rudeney

That photo is an M272, right? I think the M273 (5.5l V8) is a bit different. It only has cam plugs on the left head, and both are snap-in caps - no bolts. The right head has nothing on the back of the head to leak.

Glyn M Ruck

Thats a M272 - should have stated. I was not aware the V8 was different.

Glyn M Ruck

Ah - it depends how the engine is spec'ed for the vehicle.

Bulletin:

Oil Seepage From Back of Cylinder Heads on Mercedes M272/273 Engines


This bulletin affects all Mercedes vehicles equipped with M272/273 engines built up to June 2008 production date.



If you receive customer reports of oil seeping from Mercedes vehicles equipped with M272/273 engines, the cause could be the round plastic expansion plugs on the back of the cylinder heads (Figure 1). To resolve, perform the following.

Note: As of June 2008 production, new improved plugs were phased into production.

There are two different size plugs as listed below:
• p/n - A000 998 55 90 – 2 small expansion plugs
• p/n - A000 998 56 90 – 1 large expansion plug (engines without vacuum pump)

Remove the existing plugs, clean the opening and install new plugs (Figure 2). Note: The plug opening should free of grease or oil. No sealer should be used in the installation of the new plugs.

pth611

Hey guys, I hope I'm not hijacking this thread but it went perfectly with my problem. I have the oil leaking on to the exhaust issue. I had a burning oil smell on my driver side as well as I saw smoke. I was quoted on valve cover gaskets to be a $560 job on my clk500. is that right?

Glyn M Ruck

I can't comment on whether the price is reasonable or not. But frequently the problem is not the cambox gaskets but rather the cam bore blanker plugs/expansion plugs that we are talking about here.

Glyn M Ruck

M273

255 A 000 997 76 20 EXPANSION PLUG
AT CYLINDER HEAD 002
260 A 000 997 78 20 EXPANSION PLUG
VACUUM PUMP NO LONGER APPLICABLE 001

OK - all engines 272/273 should have 2 small expansion plugs.
Some engines without vacuum pump will have the large expansion plug.
Latest engines will have screwed on cover as in my pic in place of the large expansion plug.
Note that P/N's quoted here have been superceded by those in the bulletin above.

nundad

Got my replacement caps. Able to take off the front engine cover. How do I remove the back. Looks like it snaps out but before I go pulling on things, is there a specific way to remove it?
08 cls550