oil leak
Thread Starter
Senior Member
Joined: Jul 2007
Posts: 421
Likes: 14
From: Bay Area
2004 E500 CLK320
oil leak
There's a short, hard plastic piece connecting the oil filler cap to the engine block and oil is leaking under this "oil filler neck". Has anyone seen this problem? Can this piece be replaced? I tried to twist it off by hand, but I can only wiggles slightly. Any idea? I did a search on this forum and apparently no one has mentioned this problem.
Thread Starter
Senior Member
Joined: Jul 2007
Posts: 421
Likes: 14
From: Bay Area
2004 E500 CLK320
Never mind, I just figured it out this morning. There's a tap on the filler neck preventing it from turning. I simply pull it straight up and turn it counter clock wise at the same time, and it twists off easily. I only need to replace the o-ring gasket, and in fact it uses the same gasket as the oil filler cap. And the oil filler cap also fits onto the oil filler opening. So in fact, you can remove the filler neck and don't need to put it back on. The filler neck makes it easier for us to pour oil into the engine without removing the engine plastic cover.
Junior Member
Joined: Oct 2010
Posts: 55
Likes: 1
From: Colorado Springs, CO
2008 R320 4MATIC
oil filler leak
I too searched exhaustively for anybody with this problem, and for a replacement part. So glad to find your post. You descreibed the exact problem I am having with my E430. Though we have different engines I can imagine the problem is the same. I will post results as soon as I try it (I am away from home for another week). Everybody always has something to say about the burning oil smell which is totally annoying
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Joined: Mar 2010
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From: Land of mountains, cheese, chocolate and watches
12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
I also have a burnt oil smell from time to time with my C43. Thought that with over 160k the engine may be burning oil, but the oil level doesn't budge at all, so that has been ruled out. I must admit I havn't checked seriously around in the engine bay to see where the oil may be coming from (valve cover perhaps?) Will check what was mentioned by SZMB, but I didn't understand completely 
Any pics available?? 
Any pics available??
Junior Member
Joined: Oct 2010
Posts: 55
Likes: 1
From: Colorado Springs, CO
2008 R320 4MATIC
oil cap filler leak
Here are the pics. You can see the oil leaking from the bottom of the plastic filler neck. I removed the filler neck and put the oil cap directly on the valve cover. The gasket on the oil cap seemd much more pliable than the gasket on the filler neck, probably hardened from years of oil exposure and heat. Upon driving, I can still smeel some burning oil. This may be residual, the oil spilled from the neck was quite an amount. I will see if after a few days it goes away. In the meantime, does anyone kow where some new oil cap/filler neck gaskets can be had? All I've been able to find are oil caps.
Last edited by Sierra Grande; Oct 18, 2010 at 06:15 AM. Reason: sp
Newbie
Joined: Aug 2008
Posts: 1
Likes: 0
E430
Oil cap/filler neck gasket part# 111-018-00-80 is available at dealer.
I tried pull the filler neck straight up and turn it counter clock wise at the same time but it didn't come out, it just moved about 1/4".
Using the flat head screw driver to push the little tap up and turn it counter clock wise at the same time, it comes off.
I tried pull the filler neck straight up and turn it counter clock wise at the same time but it didn't come out, it just moved about 1/4".
Using the flat head screw driver to push the little tap up and turn it counter clock wise at the same time, it comes off.
Last edited by HTN-E430; Oct 12, 2012 at 07:36 PM. Reason: Added how to.
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Junior Member
Joined: Oct 2010
Posts: 55
Likes: 1
From: Colorado Springs, CO
2008 R320 4MATIC
Hey I thought I better update. Thanks for the suggestions.
I'm pretty sure all the oil came from the filler neck. After I changed the gasket and cleaned up the motor, the oil smell went away completely. I never had any more oil leaks after that. Amazing motor with 200k and no oil leaks except one superficial little gasket problem! I ended up getting the oil cap gasket on autohaus, it's the same gasket for the neck and cap so I replaced both.
BTW, I bent the one of the metal tabs on the bottom of the filler neck getting it off
It was prety easy to bend back and re-install. It doesn't come off quite like the filler cap......
I'm pretty sure all the oil came from the filler neck. After I changed the gasket and cleaned up the motor, the oil smell went away completely. I never had any more oil leaks after that. Amazing motor with 200k and no oil leaks except one superficial little gasket problem! I ended up getting the oil cap gasket on autohaus, it's the same gasket for the neck and cap so I replaced both.
BTW, I bent the one of the metal tabs on the bottom of the filler neck getting it off
It was prety easy to bend back and re-install. It doesn't come off quite like the filler cap......
