[E90_boostjunky]

Alright well, i just made a thread last night about weird noises i was hearing, and i jinxed my self.. i just got done doing some city driving, for like an hour i was bored, just driving around, i pull into my garage when i get home and i let my car cool down for about 5 minutes (its a habit). anyway when i turned my car off i heard this humming noise coming from inside the engine bay on the left side. it went away after about 3-4 minutes. any suggestions on what it is? please help sorry for these stupid threads im making. i got an oil change tommorow im gonna ask the technician about it. heres a video.

[TheTal0n]

woah, maybe open up your DME box and listen, or try cycling your water pump. see if it makes it.
totally lost on that.

[E90_boostjunky]

Originally Posted by TheTal0n

woah, maybe open up your DME box and listen, or try cycling your water pump. see if it makes it.
totally lost on that.

how do you cycle your water pump?

[E90_boostjunky]

i just went out and started the car again left it running for like 3 minutes and turned it off, it didnt make the noise. im just paranoid as hell now...

[TheTal0n]

Originally Posted by E90_boostjunky

how do you cycle your water pump?

17) Insert the key into the dash slot and hit the starter button (but don’t start the engine – e.g. keep your foot off the bake/clutch).
18) When the ignition is on, set the heater to the highest temp (84 deg.) and set the fan on low.
19) Hold down the accelerator pedal for 10 seconds then release. This activates the water pump and it will cycle for about 12 minutes to vent all the trapped air into the coolant reservoir (it sounds like a min washing machine). Don’t open the reservoir cap or bleed screw during the venting process! (you’ll have start the process over) You may want to hook up a extra battery to the under-hood jumper points to keep the car’s battery from running down.

Thanks to ENTITY and his coolant flush thread!

[E90Company]

Lol, you are 100% fine. It's your water pump running for awhile extra to cool those turbos while the engine is off.

[E90_boostjunky]

Originally Posted by E90Company

Lol, you are 100% fine. It's your water pump running for awhile extra to cool those while the engine is off.

thanks man, i appreciate it! you always seem to have the answer to everything can i buy you dinner LOL?

[TheTal0n]

Originally Posted by E90Company

Lol, you are 100% fine. It's your water pump running for awhile extra to cool those turbos while the engine is off.

I thought it might be that, or maybe extra weird buzzing sound the computers make when shutting down.

[E90_boostjunky]

Originally Posted by TheTal0n

17) Insert the key into the dash slot and hit the starter button (but don’t start the engine – e.g. keep your foot off the bake/clutch).
18) When the ignition is on, set the heater to the highest temp (84 deg.) and set the fan on low.
19) Hold down the accelerator pedal for 10 seconds then release. This activates the water pump and it will cycle for about 12 minutes to vent all the trapped air into the coolant reservoir (it sounds like a min washing machine). Don’t open the reservoir cap or bleed screw during the venting process! (you’ll have start the process over) You may want to hook up a extra battery to the under-hood jumper points to keep the car’s battery from running down.

Thanks to ENTITY and his coolant flush thread!

thank you!!

[osukf09]

Kind of reviving an old thread here, but since there is a video with my exact current sound I figure I'd utilize it.

The difference here aside from the OP is that I already had the occasional quiet buzzing/humming noise after engine off that I assumed was the waterpump. NOW, the sound is similar but much louder (like in the video) and seems to come on more frequently within the last 2 days.

Am I still in the clear, or is this perhaps waterpump leading to failure? I'm just a little paranoid here.

[osukf09]

Perhaps one sound is fuel pump priming and other sound is waterpump cooling turbos?

[E90_boostjunky]

Originally Posted by apjr09

Kind of reviving an old thread here, but since there is a video with my exact current sound I figure I'd utilize it.

The difference here aside from the OP is that I already had the occasional quiet buzzing/humming noise after engine off that I assumed was the waterpump. NOW, the sound is similar but much louder (like in the video) and seems to come on more frequently within the last 2 days.

Am I still in the clear, or is this perhaps waterpump leading to failure? I'm just a little paranoid here.

I think its just the water pump. I ended up replacing my water pump & thermostat in April. Notice that my thread was made last October so I wouldn't really worry about it unless it sounds horrible. Good luck.

[osukf09]

Ok, thanks for the info. I've also been monitoring oil temps more closely and it seems like the engine is heating up more quickly, but that could just be my eyes playing tricks on me as I don't usually watch the oil temps with the same kind of precision...

[RMG]

Originally Posted by E90_boostjunky

I think its just the water pump. I ended up replacing my water pump & thermostat in April. Notice that my thread was made last October so I wouldn't really worry about it unless it sounds horrible. Good luck.

don't panic...this is not the water pump, it's a vacuum servo (for the turbochargers) problem and you might need two new pressure converters/transducers. Simple and relatively inexpensive to replace. Have the car checked by BMW showing them the video ( N.B. there will be no error codes), chances are they've seen this many times before. Hope this helps.

[norsairius]

Originally Posted by TheTal0n

17) Insert the key into the dash slot and hit the starter button (but don’t start the engine – e.g. keep your foot off the bake/clutch).
18) When the ignition is on, set the heater to the highest temp (84 deg.) and set the fan on low.
19) Hold down the accelerator pedal for 10 seconds then release. This activates the water pump and it will cycle for about 12 minutes to vent all the trapped air into the coolant reservoir (it sounds like a min washing machine). Don’t open the reservoir cap or bleed screw during the venting process! (you’ll have start the process over) You may want to hook up a extra battery to the under-hood jumper points to keep the car’s battery from running down.

Thanks to ENTITY and his coolant flush thread!

Would there be any benefit to doing this on a periodic basis? Also, how much could it really run down the battery (I don't have an extra battery or convenient access for a trickle charger and such).

[osukf09]

Originally Posted by RMG

don't panic...this is not the water pump, it's a vacuum servo (for the turbochargers) problem and you might need two new pressure converters/transducers. Simple and relatively inexpensive to replace. Have the car checked by BMW showing them the video ( N.B. there will be no error codes), chances are they've seen this many times before. Hope this helps.

Hm, interesting. I'll have to take it in to get it checked out. Just ran out of CPO warranty, so may be best to use an indy. I did have a turbo replaced several months ago under warranty, think the coverage on that work would extend to this issue?

Also, the noise is very on/off. It starts up immediately after powering down the car, but will turn on for a few seconds, then sound like it's choking and stop, then restart again for a few seconds. Very strange...

[RMG]

Originally Posted by apjr09

Also, the noise is very on/off.

...yes, typical for this particular issue. That's why I suggested to take the the video with you.
Not sure about the warranty part, you need to ask the dealer. But something possibly happened during the repair, these two pressure converters are in the same engine area (part of the vacuum control assy and connected to the turbo's) and it might be possible the tubing or the converters got damaged or were incorrectly re- installed. Knowing the BMW of NA techs work ethic and the general skills it is very likely they screwed up something. Looking in retrospective I had mine starting buzzing immediately after a routine service visit, on my way home actually....nothing surprises me anymore when dealing with these "BMW certified" centers of incompetence.