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My car, Mercedes C250 Sport W204 (M271 DE18LA EVO 271.860) , had the same symptomes as described previous comments, eg.: noise between 1200-1500rpm when slowing down.
Complete timing system was replaced, adjusters, central valves, valve solenoids, all sliding rails, all tensioners, tensioner bracket, chains, pins, position sensors! Firstly only the mechanical parts were replaced and later the electrical parts (solenoids, sensors). After each step the engine was better and better, but still not flawless. Everyone thought and everytime the oil pressure is the issue. Never was!!!
The break vacuum pump (A271 230 1665) is attached to the exhaust camshaft. Only 2 screws hold it, so I managed to replace it, here is a useful guide for the process (which is a little bit tricky because of the small room to loosen and tighten the 2 screws): https://youtu.be/Vt_aTRc0_So
My assumption is the pump created unnecessary and not constant load to the timing system via exhaust camshaft. The difference of the rotational resistance between the old and the new pumps was clearly felt by hand.
Good luck!
what's the consequence of not changing out the brake vacuum pump in the long term?
Also Is there a post where (other than this one) we can listen to what a brake vacuum pump failure sounds like? all the ones ive heard from other sources on brake vacuum pump failure sound completely different from the video you posted (which is identical to mine).
EDIT: has this problem ever thrown any codes for any one experiencing this? if so, which.
Also please excuse my rudimentary understanding of the mechanics, but how does a brake vacuum pump would be culprit when this problem only occurs during lowering rpm (either by braking or by letting go off the gas) and sometimes by keeping an a constant rpm on the gas pedal?
Thank you again
I fix the supid noise, after all smart *** mechanical guys from Mercedes make me to change timing chain, tensioner,variable timing ,sensors, everything, VACUM BREAK PUMP failure and once I replace it..no more this chain sound!!! Trust me I hate to spent money on fake problems!!!!!!! All information guys you need, like video, or explanation, I m here!
m271 evo
w204
1.8L 4Cyl
156hp
250nm
how does the vacuum pump link to the rattling of chain noise in low rpm?
i changed tensioner, timing chain etc etc but doesnt solve the problem
I’ve been experiencing these same noises as mentioned above. Rattling when I remove my foot off the gas and while RPM is dropping. Read this forum and thought y’all finally solved it with the vaccum pump. Changed my vaccum pump 10 mins ago and the noise is STILL THERE! 😩😩
I’ve been experiencing these same noises as mentioned above. Rattling when I remove my foot off the gas and while RPM is dropping. Read this forum and thought y’all finally solved it with the vaccum pump. Changed my vaccum pump 10 mins ago and the noise is STILL THERE! 😩😩
could it be the vacuum hose attachd to the pump is also defective?
could it be the vacuum hose attachd to the pump is also defective?
thanks for the suggestion on the hose, sincerely appreciate this.
there’s only one hose connected to the pump and it’s the one at the top. Is that the hose you’re referring to? If yes, will get this sorted tomorrow and update here.
thanks for the suggestion on the hose, sincerely appreciate this.
there’s only one hose connected to the pump and it’s the one at the top. Is that the hose you’re referring to? If yes, will get this sorted tomorrow and update here.
yes thats the hose I’m referring to, worth a shot replacing it
i dont know of any other hoses that are attached to it
genuinely hope this fixes it, keep us posted
the parts store here does not have the hose in stock yet. Eagerly waiting! Has it worked for anyone here? Keen to know if this will fix this annoying problem
my local store does not have stock for original vacuum pump.. only OEM.. so i have not try changing yet.
no estimated date, I actually thought they don’t sell that hose at all as I couldn’t find the part number and they may have just told me it’s out of stock because of that. I then asked a scrapyard to check if they have any C200 CGIs (which is the same model as me) that they can help me remove the hose from and I’ll buy it from them. Still waiting for a response. Do you happen to have the part number?
no estimated date, I actually thought they don’t sell that hose at all as I couldn’t find the part number and they may have just told me it’s out of stock because of that. I then asked a scrapyard to check if they have any C200 CGIs (which is the same model as me) that they can help me remove the hose from and I’ll buy it from them. Still waiting for a response. Do you happen to have the part number?
Ive attached two links which I believe are part of the vacuum hose assembly (correct me if I'm wrong), how much did you pay for the pump itself if you don't mind me asking?
Ive attached two links which I believe are part of the vacuum hose assembly (correct me if I'm wrong), how much did you pay for the pump itself if you don't mind me asking?
yes thats the hose I’m referring to, worth a shot replacing it
i dont know of any other hoses that are attached to it
genuinely hope this fixes it, keep us posted
changed the hose and the sound is still there 😩😩 is there anything else you did that might have fixed this problem? And.. has the sound reappeared for you or it’s gone for good?
changed the hose and the sound is still there 😩😩 is there anything else you did that might have fixed this problem? And.. has the sound reappeared for you or it’s gone for good?
would it possible to attach a video capturing the noise just to confirm we're experiencing the same thing?
I haven't replaced anything yet since I'm away from my car and havent used it in a while, but according to Mr_X_45 and vlac (above) they successfully got rid of the noise by replacing the pump.
if the noise is indeed the same but didn't go away by replacing the pump as you have done, then perhaps the best course of action would be to take it to a shop and get their opinion on it.
quick update, I just took my car in to the mechanic and replicated the sound by holding the car at around ~1200 rpm while they listened with a stethoscope - they said the brake vacuum pump (which some have found to be the culprit) was quiet and they said the rattling noise was coming from the exhaust manifold gasket.
I don't know how that could explain the rattling noise and that its contrary to the brake vacuum pump solution thats worked for some here.
If anyone knows whether or not the exhaust manifold gasket could be a plausible explanation for the noise, id appreciate your input!
quick update, I just took my car in to the mechanic and replicated the sound by holding the car at around ~1200 rpm while they listened with a stethoscope - they said the brake vacuum pump (which some have found to be the culprit) was quiet and they said the rattling noise was coming from the exhaust manifold gasket.
I don't know how that could explain the rattling noise and that its contrary to the brake vacuum pump solution thats worked for some here.
If anyone knows whether or not the exhaust manifold gasket could be a plausible explanation for the noise, id appreciate your input!
I also replaced the vacuum pump, but it didn't work. Is it effective after replacing the intake manifold? I want to know the progress.
Hi all, same problem with knocking sound. Chain and everything else replaced 13k miles ago, new brake pump and the line changed 2 weeks ago, knocking sound when accelerating, decelerating or when stationary around 2000 rpm. Any help is greatly appreciated
Hi all, same problem with knocking sound. Chain and everything else replaced 13k miles ago, new brake pump and the line changed 2 weeks ago, knocking sound when accelerating, decelerating or when stationary around 2000 rpm. Any help is greatly appreciated
is it a knocking sound for you? I found it to be more of a metallic rattle with varying frequencies- when i took it to the mechanic, they said the noise was coming from the exhaust manifold gasket. Not sure if the engine is actually knocking for it to make that sound
so far, no reliably definitive solution has been found unfortunately
is it a knocking sound for you? I found it to be more of a metallic rattle with varying frequencies- when i took it to the mechanic, they said the noise was coming from the exhaust manifold gasket. Not sure if the engine is actually knocking for it to make that sound
so far, no reliably definitive solution has been found unfortunately
I recorded the sound yesterday after work, please have a listen if this is similar to your sound?
sounds somewhat similar - the sound is primarily present when the rpms being held constant
take a listen to my recordings and judge whether they're identical to yours or not
01-09-2023, 09:20 AM
