Hello, all,

I've done a search on this topic for the W202, and it seems earlier posters have had a slightly different problem from mine.

The locks on my '97 C230 work fine, both locking and unlocking. However, in the last month or so, when I lock or unlock the doors (either with the key fob, a key in the passenger door lock, or via the dash switch), I hear a fairly loud "thuttering" sound which appears to come from the passenger side rear door. Behind this, I know, is where the vacuum pump is located. However, unlike the other posts I've read, the vacuum pump does not keep on running after the doors are locked/unlocked.

Is this a sign of trouble to come? Rubber seals going? How can I get to the vacuum pump, and what do I look for (yellow hoses are the ones for the pump, right)?

TIA,

__________________
* *
-- Paul W. (The Benzadmiral)
('03 Buick Park Avenue, charcoal/cream)
Formerly:
'97 C230, smoke silver/parchment; '86 420SEL, anthracite/light grey; '84 280CE (W123), dark blue/palomino

kind of coincidental but I had the same kind of problem on my `98 202 a few weeks ago.
The problem went away and I am not sure why, but what I did do is lubricate the locking pin for the fuel filler door with 303 rubber protectant. I sprayed lots of 303 around that fuel filler lock near the gas cap and it helped me

test to see if the noise is from the fuel filler door lock.

Ethan,

Great idea. Excuse me while I smack my forehead for not thinking of it!

To reach the locking pin, do I have to remove part of the trunk liner, or could I reach it from outside, i.e., through the fuel filler door?
.

__________________
* *
-- Paul W. (The Benzadmiral)
('03 Buick Park Avenue, charcoal/cream)
Formerly:
'97 C230, smoke silver/parchment; '86 420SEL, anthracite/light grey; '84 280CE (W123), dark blue/palomino

do it from the outside, just open the gas filler door and spray away, as I recall there is a rubber gaiter at the base of the locking pin, I saturated that with 303 along with the rubber surround of the gas filler tube and the groaning noise I was getting went away. Of course I had my gas cap tightly on.

Hope it works for you.

i have the exact same problem on my merc c200 w202 1997 car.

i will use wd40 lubricant spray that we get here in the u.k. to see if it cures the problem and post the resutlt on here

WD40 isn't a good lubricant it is more of a cleaner. I don't think WD40 will help rubber on the long run either.

Glycerin rubbed on would probably be better.

Let us know what happens