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Hello all,
I've been dealing with a rattle for a couple of months on my E400 (3.0 Bi-turbo) M276.820. I have a rattle at some rpms, it started barely noticeable but now it's driving me nuts... I did some research and found out about the wastegate rattle, had it checked by the mechanic but he states that they work fine and he thinks it's something before the turbos, perhaps intake manifolds? Do these engines have swirl flaps or something similar?
I've attached 2 clips I took , one is from last year the second from last week (links below) Any advice is much appreciated, thank you.
* I do not have any error messages popping up, no CEL, no nothing, car behaves normally.
Last year: https://youtube.com/shorts/iQORIadoIC4?si=eFtcgZwy95wQTOq1
Last week: https://youtube.com/shorts/DEKZ8Ju_hCY?si=JkFa0hiXZsqkqP4A
Your engine sound is somewhat "busy", nothing unusual - These early GDI engine are not quiet.
The acceleration does not sound right as if starved.
> What is your current mileage now?
> Have you checked your fuel rail pressure.
Engine sounds it's struggling for fuel under acceleration.
-- Simple ECU data will read pressure.
-- Tank module will read low side pressure fuel supply.
> Read your idle fuel trim: both LTFT data... lean?
will be telling how your engine is running.
No worries this is not complicated.
Last edited by CaliBenzDriver; Sep 27, 2025 at 05:45 PM.
Your engine sound is somewhat "busy", nothing unsual - These GDI engines are not really quiet.
Its the acceleration that does not sound right as if starved.
> What is your current mileage now?
> Have you checked your fuel rail pressure it sounds it's struggling for fuel under acceleration.
-- Simple ECU data will read pressure.
-- Tank module will read low side pressure fuel supply.
> How old is your ignition tune-up... ok less than 40kMi or above?
> Read your fuel trim data... lean?
No worries it is not rocket science.
I have 211kkm, no I didn't check it... But there are no errors as far as I know, I'll check Monday , the acceleration can sound like that because I was trying to constantly make it rattle ) But I do not know how these can produce that sound, or what exactly... But thanks for the suggestion
I have 211kkm, no I didn't check it... But there are no errors as far as I know, I'll check Monday , the acceleration can sound like that because I was trying to constantly make it rattle ) But I do not know how these can produce that sound, or what exactly... But thanks for the suggestion
211kKm are equivalent to 130kMi.
To be clear I don't hear the loud standard "VVT rattling" but the lean injector crickets ("rattlesnake").
There are a few maintainance parts you can throw at your engine already.
Your phasers do not sound rattling...
Secondary Tensioners are good to swap.
Ensure you have reliable ignition plugs.
The cricket sound is from the injectors based on what injection timings they are using.
Nothing wrong with these injectors.
Read scanner data :
Both low/high fuel pressures
LTFT values.
Last edited by CaliBenzDriver; Sep 27, 2025 at 07:06 PM.
MB has software update to reduce wastegate rattle.
I am more concerned on your turbo whistling sound while your did not even do WOT to 6,000 RPM ish yet.
There is a small possibility you have a small boost leak and if 211K KM, I am not suprised.
Or did you install those dumb-azz blow off valve ?
Your engine is the same as mine, I am very familiar with it by sound.
Last edited by S-Prihadi; Sep 29, 2025 at 02:48 AM.
Apparently there was just a miscommunication, the mechanic thought I was talking about the vacuum actuator and he was saying about the flaps inside, when we were both talking about the same thing )) We also did a full scan and there was only one low turbo boost pressure reading, nothing else, did a joy ride , scanned again, clear.
Soo I was right from the beginning all along, he put pressure to hold it sealed and it was still rattling, when the flaps are completely opened, no rattling. So he thinks that there is play between the actuator and flap on the left driver's side turbo.
Anyways, I know these are common, how have you managed to solve it? I've seen some repair kits online but don't know how effective they are.
The only time the turbo wastegate flaps/coins rattle , it is when at light load . During full open or full closed, it will not rattle. https://www.ebay.co.uk/itm/276466042597
The said rattle is not at the flap to turbo hole/port, but at the interface marked below A & B. B shaft goes into A bushing.
If during full closing of the flap towards the turbo port/hole and you still get rattle, that is when you will loose boost too because the wastegate components are wearing out and this is normal
after high mileage. If you had the low boost code, and the hiss I heard, there is a chance the item #1 flap surface is already not good anymore and thus it can't keep
pressure at the port/hole.
Low boost code can also come from other devices too.
Here is the flow chart Vacuum pump>>>plastic vacuum hose>>>electric vacuum solenoid>>> vacuum hose>>>> Y split hose >>>
Y split>>>>RIGHT OR LEFT side vacuum actuator >>> its rod pulling the wastegate flap of LEFT or RIGHT side turbo
Above is handling exhaust or hot side of turbo
The cool charged side of the turbo or the air intake side of the engine has areas boost can leak too. But it is not the scope of this topic of rattle.
Your hiss sound is at/from the cool charged side.
So keep in mind, boost loss can happen during production ( hot side ) and during delivery ( cool side ).
Since M276.8 only has 1 boost sensor and 1 MAP, it can not tell which L or R turbo system causing the low boost.
The only time the turbo wastegate flaps/coins rattle , it is when at light load . During full open or full closed, it will not rattle. https://www.ebay.co.uk/itm/276466042597
The said rattle is not at the flap to turbo hole/port, but at the interface marked below A & B. B shaft goes into A bushing.
If during full closing of the flap towards the turbo port/hole and you still get rattle, that is when you will loose boost too because the wastegate components are wearing out and this is normal
after high mileage. If you had the low boost code, and the hiss I heard, there is a chance the item #1 flap surface is already not good anymore and thus it can't keep
pressure at the port/hole.
Low boost code can also come from other devices too.
Here is the flow chart Vacuum pump>>>plastic vacuum hose>>>electric vacuum solenoid>>> vacuum hose>>>> Y split hose >>>
Y split>>>>RIGHT OR LEFT side vacuum actuator >>> its rod pulling the wastegate flap of LEFT or RIGHT side turbo
Above is handling exhaust or hot side of turbo
The cool charged side of the turbo or the air intake side of the engine has areas boost can leak too. But it is not the scope of this topic of rattle.
Your hiss sound is at/from the cool charged side.
So keep in mind, boost loss can happen during production ( hot side ) and during delivery ( cool side ).
Since M276.8 only has 1 boost sensor and 1 MAP, it can not tell which L or R turbo system causing the low boost.
Thank you so much,
and I am very sorry for this late reply, after my last reply I honestly forgot to check the forum, as i was "calmed" by the fact it wasn't a huge deal. Now though it started to sound much more often, and it really bothers me, so i entered to search again for more topics here and noticed your comment
In the mean time, has yours gotten worse? have you solved it or left it as is? I will record a video later and upload it here, how it sounds now..
I've seen full kits from mamba aswell, for a resonable price (as to replacing the whole turbo), do you have any knowledge if it is a straight fit or if it needs some physical modifications? I've seen on some bmw's people drilling a hole to make it bigger for part 2 to fit, but i am anxious it might damage the housing....
Thanks again.
Thank you so much,
and I am very sorry for this late reply, after my last reply I honestly forgot to check the forum, as i was "calmed" by the fact it wasn't a huge deal. Now though it started to sound much more often, and it really bothers me, so i entered to search again for more topics here and noticed your comment
In the mean time, has yours gotten worse? have you solved it or left it as is? I will record a video later and upload it here, how it sounds now..
I've seen full kits from mamba aswell, for a resonable price (as to replacing the whole turbo), do you have any knowledge if it is a straight fit or if it needs some physical modifications? I've seen on some bmw's people drilling a hole to make it bigger for part 2 to fit, but i am anxious it might damage the housing....
Thanks again.
Here is a clip i recorded, the rattling in motion, stationary and also checked the Vaccum Valve, as i've seen some hints that it might also have an effect. The valve is not spitting oil, but it is also not puffing, but pulling, i do not know if that is correct, the other clips i saw regarding it i've seen it puff...
I can hear the normal turbo wastegate rattle in neutral grear, engine bay video.
You vacuum pumps sounds OK too, it still sucks, but best to measure its sucking power which should be close to 25 inch hg or higher.
My turbo wastegate rattle is not getting worse, last year when I replied to your post and this year 14th March I only done only maximum 1,000 KM at best....LOL.
I can hear the normal turbo wastegate rattle in neutral grear, engine bay video.
You vacuum pumps sounds OK too, it still sucks, but best to measure its sucking power which should be close to 25 inch hg or higher.
My turbo wastegate rattle is not getting worse, last year when I replied to your post and this year 14th March I only done only maximum 1,000 KM at best....LOL.
Oh, okay, from the clips i tought the valve was supposed to spit not pull ))
As for the integrity check, little to advance for me, i'll leave that to my mechanic, i hope to get it solved as soon as possible as it's driving me nuts.
Well, As seen in the clip the whole Wastegate arms move ( sorry for the language, i'm from Romania) - they have a lot of play in it so they need to be changed. The mechanic said that it might be possible that it might also be broken in the arm so there is a possibility for them to fall down. I have bought the repair kit - should be here in 1-2 weeks. I will ask the mechanic to take some pictures of the installation aswell to document it here
Well, solved it. Unfortunately the mechanic couldn't take any relevant photos of the process, as he was working solo on the car.
Both turbos needed to be taken down and the old wastegates had to be drilled out, pain in the *** honestly.
But at least the result is good. No more rattles, i also feel like the car is building low-end boost much better.
If it bothers anyone else reading these, it does work, if not, you choose if you want to commit on changing them or not
Well, solved it. Unfortunately the mechanic couldn't take any relevant photos of the process, as he was working solo on the car.
Both turbos needed to be taken down and the old wastegates had to be drilled out, pain in the *** honestly.
But at least the result is good. No more rattles, i also feel like the car is building low-end boost much better.
If it bothers anyone else reading these, it does work, if not, you choose if you want to commit on changing them or not
Yes, that was the rattle, i wanted to add videos of how it sounds now and how the old ones looked but the attachments were too big to add here. I'll upload them to my personal yt and attach
Well, solved it. Unfortunately the mechanic couldn't take any relevant photos of the process, as he was working solo on the car.
Both turbos needed to be taken down and the old wastegates had to be drilled out, pain in the *** honestly.
But at least the result is good. No more rattles, i also feel like the car is building low-end boost much better.
If it bothers anyone else reading these, it does work, if not, you choose if you want to commit on changing them or not
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) But I do not know how these can produce that sound, or what exactly... But thanks for the suggestion
