Moreira_C230

Before I go on my rant, has anyone else had a problem with the oil cap on their M272?

[rant]
Yesterday morning: I am on the way to work on my normal 14 mile commute. I pull onto the highway, look down for a second to plug in my phone charger, look and look back up (maybe a 2 second window). I look out the back window and I cannot see more than 10 feet behind me. My car is poourrring out grey/black smoke and the cabin instantly starts to smell of oil. I pull over on the side of the highway (rt 2 west for you boston guys) and immediately shut the engine off. For a second I am afraid to open the hood as I don't have a flipping clue what I would find. Open the hood.....oil cap.....gone. There was oil all over the right cylinder bank, coil packs, right exhaust manifold, everything. The entire right side of my engine bay was covered in oil. This is the second time that I have had a problem with my oil cap. I even replaced my old one a few months ago as it kept leaking oil....
[/rant]

However, after some thinking, I am afraid that there may be some sort of pressure issue in the head (maybe excessive blow by?). However, there are no codes being thrown and the engine really is running beautifully, so I have no idea if it was just a faulty oil cap or if there is an actual problem...

Any ideas?

pcy

I haven't had any oil filler cap issues on my '07 C280 (M272). Something doesn't sound right... you are saying this is the second time this has happened. When you replaced the oil filler cap, when you tightened it, was it snug and tight?

johnand

Almost 100K miles on my M272, and never had that issue. Agree with PCY, something is not right.

6speedclk

I have had to use tools to get theys caps off before. If is on correctly it will not fall off. So you have a pretty strange problem.

sammydragon3

your valve cover gasket is most likely worn and/or your oil level is too high

very common on v6s since the pistons make alot of vibrations

Moreira_C230

I am not entirely sure what the problem is. The car was just in for its B-service and everything checked out just fine. The car only gets serviced at a local and extremely reputable independent Mercedes shop, so I don't think its an overfill issue. As for the valve cover gasket, I will have to take a look at it when I get home.

As for it being on snugly, I tighten it as far as the cap will go, that I am sure. The only thing I was thinking is maybe there is some vibration that over time can cause it to come lose? granted a vibration that large would probably be noticed?

LILBENZ230

And you got this info where? We have a ton of V6 C-class cars on here and this is the first I've heard anything like this.

Carsy

I would purchase a new cap if you cannot find the reason for it coming off.

Also tape it on with heavy adhesive tape if it is possible ,just in case. You can't have that happening again.