Odd elecrical hum noise when you turn the car off.

[feeshta]

Hello all. For the past week or so, I've been getting an odd electrical hum/buzz type of noise for a few seconds when I turn the car off. It is coming from under the hood, and it pretty loud. It stops when you lock the car, or after maybe 5 seconds if you don't. I'm not having any other unusual symptoms, but wondering if something is going on I should be aware of.

Anyone have any ideas on what this might be? A search didn't turn up anything that seemed like the same issue, but I might not be searching the best term.

[Yeineken]

I can't tell you exactly what it is. I have it to. I don't hear it all the time. But when I do it's very noticeable.

I've been told it's normal.

[e36addict]

It's just the throttle body humming. Completely normal, nothing to worry about.

[Dackelone]

Originally Posted by e36addict

It's just the throttle body humming. Completely normal, nothing to worry about.

or the electric water pump. Or... the LPFP(fuel pump rear of car).

Most everyone refers to this noise as a fax or laser printer warming up. It's a normal noise.

[Bimmer-Bob]

I've always heard it was the fuel pump priming but I honestly don'y know what it is, other than that my car has always done it and from what I can tell it's perfectly normal. You should hear the noises the car makes when you're coding it!

[Solo_M_Tech]

[Solo_M_Tech]

Next time leave the hood open, and when it does it, find it, and record it for us to hear. Maybe it's not just a normal sound....

[Josh (PA)]

There are a number of normal hums, but before my electric waterpump failed I had a noticeable 'different' hum when the car shut off. A week later, I was on the side of the road with a failed pump. Good luck.

Edit:

This is how I described it:

I only notice the noise after I shut the engine down. It lasts 30 secs to a minute. It sounds a lot like the DI injector tapping/knocking, but is somewhat louder. It seems to be coming from the center passenger side area of the engine bay.

It is not the normal cool down tapping/ticking you hear from the exhausts. It is a driven (mechanical) noise. It isn't the buzzy sound of the fuel pump. It isn't coming from the radiator fan or clutch.

[MZWIE]

Our cars make all kinds of noises when turned off. Every once in a while mine makes a "farting" sound as well.

[champignon]

Originally Posted by e34m5

Our cars make all kinds of noises when turned off. Every once in a while mine makes a "farting" sound as well.

Go eat some Mexican food, especially the beans, and then you and your car can do a duet

[Gangplank]

Ebox fan?

[feeshta]

Thanks for the responses so far guys. I thought I had this thread set to notify me of responses by email, but I guess not. Anyway, we have had a few days of rain here, so I wasn't really keen on trying to tinker with the car all that much.

I'll see if I can get a video this afternoon now that we finally have better weather. It's definitely a new noise, or at least much louder than before. It's not a fan sound, unless the fan were jammed possibly. It seemed to be coming from the driver's side of the engine bay, but I really need to get the hood open and try it that way to be sure.

[feeshta]

Okay, I was able to get a rather crappy video of the sound it makes. The sound is very difficult to localize, but seems to be strongest around the passenger side of the engine. It's possible it is coming from underneath, which could be the electric water pump.

Here's the video.

[u2b]https://youtu.be/6Uwpl4c8niE[/u2b]

[champignon]

Originally Posted by feeshta

Okay, I was able to get a rather crappy video of the sound it makes. The sound is very difficult to localize, but seems to be strongest around the passenger side of the engine. It's possible it is coming from underneath, which could be the electric water pump.

Here's the video.

[u2b]https://youtu.be/6Uwpl4c8niE[/u2b]

Don't know what that is, but my sense is "Not Good"

[feeshta]

Well, at least it is still under warranty. Although they will not fix it until whatever is making the noise actually fails, leaving me stranded somewhere. My money would be on water pump at this point.

[Josh (PA)]

I'd wager water pump.

[e36addict]

That's the same noise my water pump was making just days before it left me stranded...

[feeshta]

Hello again everyone. Sorry it took a while to get around to updating this. There have been several things that have happened with the car since I last posted. Firstly, I took the car back to the original dealership, BMW of Mount Laurel, again. They claimed to not be able to reproduce the problem, but in response to other issues the car was having, namely lumpy idle and a cloud of smoke from the exhaust on on occasion, they did perform a carbon cleaning. The carbon cleaning totally transformed the engine. It is now silky smooth again, where before it was often very coarse, and simply unpleasant to rev. It also pulls quite a bit harder, especially at lower revs. I'm very glad they did it, however, it wasn't without it's issues, as I will explain below.

So, fast forward a few weeks and I am down in Augusta Georgia now, for a TDY. I took it to the local dealership, Taylor BMW, and it actually made the noise for them right there in the parking lot. They affirmed that it was definitely not normal, and agreed to take a look. That confirmed that it was indeed coming from the water pump. Initially they didn't think they could do anything about it, as there were no codes stored and protocol said it should not be covered under warranty. After some discussion among themselves though, they found a way to get it covered, and replaced the water pump. In the course of doing so, they found 3 other problems, one of which was somewhat major.

The major problem was that the oil filter housing was apparently leaking a ton of oil. They said there was oil pooled up on the upper side of the lower engine cover. The problem was a blown gasket, so they replaced it under warranty. I know this wasn't an issue about a month prior, but don't know when it started or why although I suspect the previous dealership might have had something to do with it. The last time I changed the oil, about a month prior, and a week before taking it to BMW of Mount Laurel, I had that cover off the car to check on something else and it was clean.

The other two problems were relatively minor, but just add to my annoyance with the dealership where I bought the car. First, they broke the snap tabs off the intake snorkel attachment point where it connects to the filter box. You can see them intact in my video above, both are now completely broken off. Second, they broke one of the hose clamps that holds the intake system together. Both of these issues appear to have been caused when they did the carbon cleaning, I don't know if they consider me a problem customer after all of the issues they have caused me and were half-assing it, or if they just are that sloppy all the time.

They did finally get my wheels refinished, after ruining them twice, but then mailed them to my old address after I went out of the way to make sure they mailed them to my current place. Thankfully my old roommate still lives there, and he called me right away. I'm really at the end of my rope with this dealership. Wish I could just stay with the one down here in Georgia, but I'm only here for 2 months.

So, moral of the story. If your car is making the same noise, and it is still under warranty, there is a good chance you can get it covered. Also, give yourself a gift and have the carbon cleaning done, just don't take it to BMW of Mt Laurel for that, or really anything at all.