[Got-Torque]

I've noticed that something kicks on and off quite a bit while the car is parked in the garage (after getting home from a drive). What the heck is it? It's sort of high pitched, in the engine compartment. Sounds like a fuel pump but I'm positive that's not what it is. Opening a door causes it to turn on as well.

[GreekboyD]

Red scoops?

[Mrdeezy]

Jajaj

[Yozh]

Pressure converters get energized and throttle plate does as well. Why? Who knows.

[Torqu3]

Is it the cooling fan?

[Got-Torque]

Not the fan, I've looked all over while it is on and can't find it. No red scoops for me, lol. It's not something changing state or position, something is turning on and running for a good 2 min then shutting off...

[Torqu3]

And this is when the engine is turned off? I notice sometimes when I am working on my car, I hear a tick and then a high pitched noise, but it only lasts for about 10 seconds. And has no apparent pattern to it.

[Got-Torque]

Yes. Engine off, keyfob out of car. Pop the hood and my engine cover is removed. It's very noticeable that something is going on... my son even asked me, what's up with you car? lol

[335dlci]

It's normal. E46 have their own buzzing noise/high pitch noise.

[JuiceQuadre]

I noticed this too.. Not sure for how long it does, i think its normal

[Thecastle]

Speaking without any actual knowledge haha.

But it wouldn't surprise me that it also energizes the low pressure fuel pumps too. A lot of direct injection cars prime the fuel pumps when you open the door. my vw would,do this.

[ASBSECU E93]

^This. Most cars have a 'ready' process prior to start-up. when a door is opened, etc...

[lnxguy]

I've got all kinds of stuff that's making noise, popping and buzzing after the engine is off. I don't worry about it anymore.

[Wolf 335]

Originally Posted by Got-Torque

I've noticed that something kicks on and off quite a bit while the car is parked in the garage (after getting home from a drive). What the heck is it? It's sort of high pitched, in the engine compartment. Sounds like a fuel pump but I'm positive that's not what it is. Opening a door causes it to turn on as well.

The high pitched noise you are hearing is the water pump circulating coolant for a short period of time after engine is off.

I hear it on mine occasionally.

[Got-Torque]

Originally Posted by Thecastle

Speaking without any actual knowledge haha.

But it wouldn't surprise me that it also energizes the low pressure fuel pumps too. A lot of direct injection cars prime the fuel pumps when you open the door. my vw would, do this.

My understanding is that on this engine, there is only the fuel pump in the tank (which I activate with my BT tool for 60 l/hr or 120 l/hr after filter changes and is pretty noticeable when it's running. The other fuel pump is the CP3 or CP4 (whichever model can't remember) that is chain driven when the crankshaft is turning. I didn't see any other fuel pump?

Originally Posted by Wolf 335

The high pitched noise you are hearing is the water pump circulating coolant for a short period of time after engine is off.

I hear it on mine occasionally.

That could be it, I didn't realize the water pump was electric on this vehicle. Is this the main engine water pump or a secondary just for the purposes of circulating coolant after shutdown?

[Wolf 335]

Originally Posted by Got-Torque

My understanding is that on this engine, there is only the fuel pump in the tank (which I activate with my BT tool for 60 l/hr or 120 l/hr after filter changes and is pretty noticeable when it's running. The other fuel pump is the CP3 or CP4 (whichever model can't remember) that is chain driven when the crankshaft is turning. I didn't see any other fuel pump?



That could be it, I didn't realize the water pump was electric on this vehicle. Is this the main engine water pump or a secondary just for the purposes of circulating coolant after shutdown?

Actually I just realized you have a diesel. I believe your pump is mechanical. So if that's the case, the noise you hear is not the pump circulating.

[BB_cuda]

We don't have the electric auxiliary pump on M57 in North America.

If I've had hood open for many hours and I push down the hood sensor, I get the same noises all over again. Definately in engine compartment.

[Torqu3]

Originally Posted by BB_cuda

We don't have the electric auxiliary pump on M57 in North America.

If I've had hood open for many hours and I push down the hood sensor, I get the same noises all over again. Definately in engine compartment.

In an earlier thread it was pointed out that the 2009 and 2010 do have an electric auxiliary pump. It's on the drivers side mounted by the wheel well, behind the coolant reservoir.

EDIT: Thread in question: http://www.e90post.com/forums/showthread.php?t=1365218 I have a 2010 and there is a pump where those 3 holes are.

[Got-Torque]

I do not have that pump on my 2011, I mounted my provent where those three holes are...

I'm sure the behavior is normal, or appears to be. Just curious what the heck it is and why BMW thinks it needs to operate so much...

[forgemarco]

Could be glow plugs getting ready

[ASBSECU E93]

I recently had to replace the aux water pump....

[Torqu3]

Originally Posted by Got-Torque

I do not have that pump on my 2011, I mounted my provent where those three holes are...

I'm sure the behavior is normal, or appears to be. Just curious what the heck it is and why BMW thinks it needs to operate so much...

I just consider them my "Engine Reminder Sounds". No need to look under the hood to see if my engine ran away or not. The sounds confirm that the engine is, in fact, where it should be. It isn't anything detrimental, since everyone else has it happening too.