DIY 05 C230 Vacuum Pump replacement




I also crawled underneath and popped off those 2 tiny rectangular covers. Sure enough the inside is slicked with some fluid. Based on the colour I think it's old ATF. I suspect it's actually from the famous leaky pilot bushing.
For more information, click on this thread.
Last edited by slammer111; Oct 7, 2016 at 12:14 AM.
BTW, sorry to keep asking about the oil consumption, but since you fixed the vacuum pump leak, has the car stopped using oil between changes?




I watched my mechanic do the full flush, to ensure he followed the MB WIS instructions. The bell housing was not touched at all during the procedure, other than the pan and the banjo bolt as per the instructions.
If the fluid in the bell housing is indeed old ATF, then I should have no more oil leaks. Unfortunately I had so many oil leaks over the last few years (cam sensors twice, vacuum pump at least twice) that I no longer have a reference point, as I've been topping up regularly. To give you an idea, I've added over 8-9L (compared to 5.5L) since the last oil change. Yes it's a lot of dead fish unfortunately, but hopefully the problem has been permanently fixed.
I'll be doing an oil change in a month or so, and will fill up the full 5.5L. Only 1 way to find out if I'm still losing oil. Stay tuned, and ask me in 6 months or so.
Last edited by slammer111; Oct 8, 2016 at 07:54 PM.
My name is Barna and i own a MB W203 C180 from 2002. My engine has a strange sound when running. Something like a broken pump or something. I have changed the power steering pump and the sound is still there. Could anyone tell me if my modell has a vacuum pump, and where is it located? Somebody told me that the vacuum pump could make that sound.
Please help me with some infos..
Thanks a lot.
C180 likely has the M271 engine? So vacuum pump is at the back of the engine:
https://mbworld.org/forums/attachmen...p-location.jpg
.. which is actually shown in detail in the first post of this very thread
Last edited by VVF; Jun 29, 2017 at 06:28 PM.




You might want to take a look at this thread.
Good luck.
The Best of Mercedes & AMG
You might want to take a look at this thread.
Good luck.
https://www.eeuroparts.com/Parts/674...ump-724807070/
This was one of my first DIY's after joining this site. Best of luck!





My understanding is that ALL M271 vacuum pumps (the earlier revisions at least) start leaking. That's why they revised the design. I do not know of a single person who did not have this problem.
I was faced with the same situation a few years back. Replaced an O ring here and there. In all cases, the leaks eventually came back after a few weeks or months. Threw in the towel and bought a new pump which solved my problem. It wasn't cheap, but it was either that or dealing with a constant mess at the back of the engine.
Just to be sure the leak wasn't at the metal gasket between the pump and engine, I also added a layer of RTV sealant on both sides when installing the new pump.
Sometimes it's easier and less trouble to spend 5x as much but solve a problem permanently.

My understanding is that ALL M271 vacuum pumps (the earlier revisions at least) start leaking. That's why they revised the design. I do not know of a single person who did not have this problem.
I was faced with the same situation a few years back. Replaced an O ring here and there. In all cases, the leaks eventually came back after a few weeks or months. Threw in the towel and bought a new pump which solved my problem. It wasn't cheap, but it was either that or dealing with a constant mess at the back of the engine.
Just to be sure the leak wasn't at the metal gasket between the pump and engine, I also added a layer of RTV sealant on both sides when installing the new pump.
Sometimes it's easier and less trouble to spend 5x as much but solve a problem permanently.
Last edited by Paul C200K; Nov 7, 2017 at 07:47 AM.




For most people, the leak is caused by the failure of the O-ring between the 2 main halves of the pump body. The problem with replacing this part is that MB does not (as of the time I attempted my fix at least) sell that part separately, as it's an "internal" part to the pump assembly. There's one off a Kia Sorrento oil filter that is the same diameter (but slightly incorrect thickness) I was able to use based on someone's suggestion here, but within a few weeks the leak was back. As I had already replaced the other (small) O-ring as well as the metal gasket, I was totally out of ideas. Only the O-ring and gasket are exterior to the engine, so the leak has to be from one of these 2 parts.
The metal gasket has a rubber coating on both sides, which is apparently enough to seal the gap. However, I wasn't taking any chances at this point. Also, there are 3 versions of this part. I replaced it with the latest one.
For most people, the leak is caused by the failure of the O-ring between the 2 main halves of the pump body. The problem with replacing this part is that MB does not (as of the time I attempted my fix at least) sell that part separately, as it's an "internal" part to the pump assembly. There's one off a Kia Sorrento oil filter that is the same diameter (but slightly incorrect thickness) I was able to use based on someone's suggestion here, but within a few weeks the leak was back. As I had already replaced the other (small) O-ring as well as the metal gasket, I was totally out of ideas. Only the O-ring and gasket are exterior to the engine, so the leak has to be from one of these 2 parts.
The metal gasket has a rubber coating on both sides, which is apparently enough to seal the gap. However, I wasn't taking any chances at this point. Also, there are 3 versions of this part. I replaced it with the latest one.
My leak seems to be between the metal gasket and the pump, but the metal gasket didn't seem to have any rubber layer on it. I only picked up the gasket last month, so I assume it's the latest version. I should have taken a picture once I'd taken the pump off, but since I didn't, I've crafted this wonderful illustration in Paint to show you where the leak comes from
. Based on this, could I rule out the O rings, as the leak hasn't occurred between the two halves?





Just curious, how did you know your timing chain and sprockets had issues? I had mine opened up and looked at last year, and was told the entire timing system was still good (I was at 180k or so at the time). They told me to return at 250-300k.
Last edited by slammer111; Oct 13, 2022 at 06:27 AM.

Just curious, how did you know your timing chain and sprockets had issues? I had mine opened up and looked at last year, and was told the entire timing system was still good (I was at 180k or so at the time). They told me to return at 250-300k.
On start up, my car made a noise that sounded like a loose chain being dragged across a surface, just for 1 second, almost as the revs settle back down after switching the car on. That being said, even after the chain and gear change, my car still makes that noise, but to a lesser extent. I had my chain and gears done at around 180 000, and chain done a second time around 250 000. My father has the W204 C180, his car started making quite a noise on start up around just before the 120 000 km maintenance plan ran out. He took it in to the dealership, they measured the chain and said it was still within tolerances, so MB head office said they weren't prepared to replace it. The local dealership though insisted that it didn't sound right, so they actually sent a voice clip to head office of the start up noise. Based on that audio clip, Head office agreed and authorised the replacement at their cost. That was just over R 30 000 (or 2 700 of your monies!!) Not sure if it's the same in your car, but my C200 w203 and my dads C180 w204 have a single chain, so it stretches. Don't know why Mercedes didn't make it a dual chain like in some other models, as this was a known flaw in the design.




Yes the timing chain is a known weak point, and has taken out quite a few vehicles with the M271 engine. Too bad there aren't any double chain solutions, though there are now aftermarket sprocket and chain solutions.
Last edited by slammer111; Jun 2, 2022 at 09:10 AM.




One thing I wanted to query on though, I have attached a photo of where the vacuum pump attaches onto the back of the motor and in one of the holes there was a build up of gunk. I cleaned it out and it was a small amount of sludge which looked like it was blocking the hole, only very thin but evenly distributed to where it had complete coverage.

My question is, does anyone know exactly how these things work? Is there a dead spot in this part of the pump with the sole purpose to gather this sludge? Is this something I should look into further?
Just hunting for a bit of information so any is appreciated


