[Neosakai]

I posted this in the n52 engine section but not much luck there. I came across some other e90/92 models that had a similar sound (even though there wasn't any resolution) thus I'm trying to see if anyone here could give me any pointers on this noise I've been dealing with



My 328i xdrive has been driving fine and all of a sudden I started hearing this very strange noise coming from the engine bay when the car is cold. Once the car is warm enough for me to start driving, I hear this grinding? howling? gurgling? noise when I accelerate very lightly from a stop until 20km/hr (12 miles/hr) then the noise goes away. The car drives fine but the noise is very noticeable.

-the noise is not rotational
-can hear it on a cold start in the engine bay, towards the back of the engine near the intake manifold
-no codes
-once the car is warm, cannot hear it from the engine bay anymore but can still hear when accelerating lightly from a stop (first video)
-the car drives fine otherwise


Tried my best to take videos of the noise.
In the first video you can see that after 20km/hr the noise goes away

In this video you can hear it from the engine bay during cold start, during 0:05-0:09 its pretty noticable

Some info about the car:

I purchased my 2011 328i xdrive two weeks ago at 164 000km (101 000 miles). I 've done the following since:

oil change - liqui moly 5w-30, Mahle filter
brake fluid
power steering fluid
transmission fluid - filter + seal
checked coolant and done the bleeding procedure multiple times

My mechanic did go back and check all the things listed above that was done and nothing seems off


Any help is appreciated!

[Neosakai]

anyone have any ideas?

[335i54n]

you say around the intake, I would look at the disa valve to start.

[Neosakai]

Originally Posted by 335i54n

you say around the intake, I would look at the disa valve to start.

Would a bad disa valve rattle instead of making a sound like water going down a drain?

Also, I think I dont have a disa valve...... do I?

[Neosakai]

the sound is still there everyday, and car still continues to drive fine. no one has heard this before? :/

[Neosakai]

anybody?

[Serf27]

Exhaust leak where the manifold connectors to the rear of the muffler?

[e90yyc]

Originally Posted by Neosakai

Would a bad disa valve rattle instead of making a sound like water going down a drain?

Also, I think I dont have a disa valve...... do I?

Correct—you do not have DISA valves.

[e90yyc]

Auto or manual?

Was the noise present before you did the transmission fluid service?

[jsunma]

(Auto, from the videos....)

I think the problem is that I'm not really hearing anything that amiss in the videos. You have a lot of lifter ticking, but that's not your complaint and it may just be the video that's amplifying that.

Whenever I've had a car that actually gurgled, it's been either an exhaust leak (but your exhaust sounds fine in the videos) or a coolant issue...generally air trapped in the heater core. You say you've bled the system several times though. Does the sound change, come, or go depending on whether you have the HVAC turned on or off? That's a long-shot...but it's a guess.

[e90yyc]

Originally Posted by jsunma

(Auto, from the videos....)

Thanks haha. Believe it or not I actually watched them but didn’t think to look in gauge cluster

OP:

Did you follow the transmission drain and refill procedure to the T? I’m guessing you did, but have to ask.

When my car was low on tranny fluid it made a gurgling/swishy noise due to the low fluid level. I guess it’s not technically “cavitation,” but this is how I would describe it.

[noah.s]

When I did my intake manifold one of the PCV hoses didn’t sit properly during install and came off when the manifold went on. Made a gurgling noise similar to this.

[Neosakai]

Still scratching my head off trying to figure out this noise...

I'm pretty confident there is enough transmission fluid and I had the pcv breather hose replaced as well because it looked oily. unfortunately those two weren't it

Things I've replaced recently:

-breather hose (the one that connects from valve cover to intake manifold)
-idler pulley/tensioner pulley/belt
-diff fluid
-spark plugs

I did kind of narrowed down that the sound should be coming from in the intake manifold area, near where the pcv breather hose connects to the angle connector. I did take out the angle connector and found that it is caked in oil. Im not sure if there was a pcv issue with the previous owner because I dont have any problems with idle and engine runs smooth. I cleaned the oil from the angle connector and now im out of ideas because that wasn't it either..

Here is a picture of where I suspect the sound is coming from (where the light is)




any other ideas? I mean I could either have the intake manifold removed again and carefully inspect for any cracks or buy a new valve cover if it is a pcv issue...Neither is a cheap job and I'm not throwing any codes so hope I dont have to resort to that as a troubleshooting option

[Neosakai]

Also to answer some of the questions from above

e90yyc: Auto, and the noise wasnt there before I did the transmission service. But the noise wasn't there on my drive back home from the mechanic after transmission service/oil change/power steering fluid/brake fluid. It started one day after ...

jsunma: the noise always sounds like whats in the video. regardless of AC on or off, unrelated to radio or any electronics from inside the cabin. I can hear it from the engine bay near the intake manifold area on a cold start, and also while accelerating at low speed like in the driving videos regardless of engine cold/warm

[Neosakai]

bump

[e90yyc]

Originally Posted by Neosakai

Also to answer some of the questions from above

e90yyc: Auto, and the noise wasnt there before I did the transmission service. But the noise wasn't there on my drive back home from the mechanic after transmission service/oil change/power steering fluid/brake fluid. It started one day after ...

jsunma: the noise always sounds like whats in the video. regardless of AC on or off, unrelated to radio or any electronics from inside the cabin. I can hear it from the engine bay near the intake manifold area on a cold start, and also while accelerating at low speed like in the driving videos regardless of engine cold/warm

Thanks! Just FYI you can reply directly to one or more posts (by quoting them) in your response, or you can tag someone by typing @ followed by their username, as this will notify them someone has responded. Nothing wrong with what you did at all, just letting you know as I didn't notice your reply until now.

Hmm. The actual noise definitely doesn't sound normal. I agree with jsunma that the lifter tick is all I can hear in some of the other clips though. Some more questions:

Is your mechanic experienced with BMWs?
Have you asked him to confirm exactly what the refill procedure was for the transmission?
Is the noise audible at idle at all? If so, when you crouch down and listen under the vehicle, does it get louder?

Maybe I'm out of my element here and am starting to throw out random guesses. I would like to think your mechanic knows what he's doing and that if your transmission fluid was low enough to cause that noise you'd be experiencing very noticeable shift issues. But at the same time, whenever an issue pops up after work was done, of course you're going to want to closely scrutinize everything that was done.

I don't think its your coolant because our water pumps are electric and therefore run independent of the engine speed. Just to be very sure it isn't anything driven by the accessory belt, try removing the belt and running your car. Does the noise change or go away? I'm guessing no, but it's an easy test that will help you rule a couple things out.

[Captain Buumer]

Maybe a flywheel?

They usually make more noises when cold and on low speeds.

[e90yyc]

Originally Posted by Captain Buumer

Maybe a flywheel?

They usually make more noises when cold and on low speeds.

OP has automatic. Not sure this would apply.

[glossmoc]

Did you ever figure this out? I’m having the same issue.

[glossmoc]

For anyone out there, I got this fixed, it was because of the heatsheild rubbing. If you have this happening you might need to replace your motor mounts so that the heat shield does not rub and also make sure the heat shield is tight.

[Draco96]

Originally Posted by glossmoc

For anyone out there, I got this fixed, it was because of the heatsheild rubbing. If you have this happening you might need to replace your motor mounts so that the heat shield does not rub and also make sure the heat shield is tight.

I have this EXACT same noise I cannot find whats rattling I've looked a few separate times. Can you describe which heat shield it was? Thanks!

[shackattack]

I too have this issue if anyone has any ideas. Sounds pretty worrying…