Hookster

My '98 C280 makes a noise when locking and unlocking the door. I've isolated the noise to the fuel door lock. How do you remove it? I can access it through the trunk, but twisting it does not seem to do anything. I don't want to force it, but before I apply much torque, I want to make sure I am doing it right. Any tips?

I'm thinking one I have the thing out I can lubricate it, or have read where there is some plastic tube that slips out of place. Need to get the thing out to see whats wrong.

YNVDIZW124

I think it's better just to live with it. Mine makes the same noise but I don't constantly have to lock and unlock my car.

Hookster

Well, we don't constantly lock and unlock it, at least more so than average. I'd prefer to not have a Benz that sounds like it is farting every time the doors are unlocked.

xvvvz

Are you sure it is the fuel door making the sound or is it the pneumatic pump located right near the fuel pump door? That sound you described sounds like it kicking into refresh the vacuum in the system. That could be due to a leak at the fuel door or it could be due to a leak elsewhere in the system. I just want to make sure you aren't going to create an additional problem

Hookster

It appears to be the locking mechanism for the fuel door. If I have my hand on it via the trunk, I can feel it kind of vibrate in conjunction with the noise. The noise is definitely coming from there. All I want to do is take the thing out so I can check it out...

xvvvz

PM/email sent

Hookster

Thanks for the information! As it turns out, mine is a bit different than the one on the document you sent. It did provide me with enough information to know what to do. For those with a '98 C280, the fuel door lock looks like this (once you have it out):



To get the thing out, all you need to do is pull up on this tab:



Be careful when you have your hands up there, expect to get cut up a bit as there are some sharp edges that sliced-up my left hand pretty good. It was easier for me to access the tab with my right hand.

Anyway, mine still makes the weird nose. Something inside is rubbing. I did try lubricating it, but it only helped a little. Maybe after time it will quite down, but there is not much you can do to these things. Replacement is probably the only option. Anyone ever purchased one of these? If so, where and how much?

Off this topic, but what is this vent for? The flaps would only allow air out, and it is tucked behind the trunk lining. Just curious.

xvvvz

My understanding is that flap is an air pressure relief outlet so that when you slam the door shut it doesn't hurt the eardrums of anyone who is sitting in the car and doesn't stress the window glass, etc.

Hookster

Interesting! Something like that would make sense. I was thinking it may have something to do with the pnuematics since the pump mechanism is right there, but the pressure relief makes more sense as the pump is probably a closed system.