WTF is this noise?!

ive seen other threads on this but they never had the answer to my problem. this noise has been happening for a couple months now. it would happen after maybe 15 minutes of driving. the noise occurs when driving less than 20mph and less then about 1500rpms when slowing down and when its in idle. the noise stops when im stepping on the gas and when i rev it in park. today, i changed the belts, nothing. i took the main drive belt off to test the pulleys(left the ac belt tho), nothing. my friend whos a mechanic is thinking it can POSSIBLY be the vacuum hose. he also thinks the noise is coming from outside the motor. we spent about 30 minutes trying to figure out what the problem is but we just couldnt figure it out. i'd rather not take it to the stealership. what else do you think the noise can be? all answers appreciated!

this would be my car from 5/22/12

Hi! my first instinct is to say the idler pulley, even though you took the belt off to check it maybe be only happening under load.
You should consider buying a mechanics stethoscope you will find it very quickly then, everyone should have one and they are cheap!!!! It could also be the water pump, even though the sounds disappears when revd I reckon the other engine noises mask it....

I say it's the water pump. My car was doing the exact same thing and that was my problem.

I changed belts, pulleys, etc.... still the same noise.

Replaced the water pump and the sound went away. One other thing about my problem was after driving for a while the sound would go away but it would always return the next morning or after the car had been sitting for awhile.

Originally Posted by All-Or-Nothing

I say it's the water pump. My car was doing the exact same thing and that was my problem.

I changed belts, pulleys, etc.... still the same noise.

Replaced the water pump and the sound went away. One other thing about my problem was after driving for a while the sound would go away but it would always return the next morning or after the car had been sitting for awhile.

Thanks for the reply btw. But how much did you pay for the water pump?

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Originally Posted by 645/333

Hi! my first instinct is to say the idler pulley, even though you took the belt off to check it maybe be only happening under load.
You should consider buying a mechanics stethoscope you will find it very quickly then, everyone should have one and they are cheap!!!! It could also be the water pump, even though the sounds disappears when revd I reckon the other engine noises mask it....

It can be the water pump. I just wish it was something not as expensive

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Originally Posted by CJ645Bern

It can be the water pump. I just wish it was something not as expensive

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It's only $165 bucks and it's in stock. This is where I got mine.

http://www.autopartsway.com/PartList.../pagenum1/tabS

Originally Posted by All-Or-Nothing

It's only $165 bucks and it's in stock. This is where I got mine.

http://www.autopartsway.com/PartList.../pagenum1/tabS

Who did u have install it? How many hours did it take?

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my car is making same noise but not as bad after fixing a coolent leaking problem. lmk your out come thx

Originally Posted by CJ645Bern

Who did u have install it? How many hours did it take?

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That's the kicker. I work for DOD and I had this done while living in the Philippines. Even at the dealership it only cost me $50 labor and I bought the part myself.

I have no idea what it would cost stateside.

I am glad I brought my 6er with me since all the crazy expensive stuff was so much cheaper when I was there. I am in Cambodia now and labor is even cheaper. I just buy my own parts.

Originally Posted by All-Or-Nothing

That's the kicker. I work for DOD and I had this done while living in the Philippines. Even at the dealership it only cost me $50 labor and I bought the part myself.

I have no idea what it would cost stateside.

I am glad I brought my 6er with me since all the crazy expensive stuff was so much cheaper when I was there. I am in Cambodia now and labor is even cheaper. I just buy my own parts.

Ohhhh that's cool lol since I'm filipino. I wish Bmw parts were cheap period!

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?The water pump is driven by the belt. It should not make noise bcuz we took the belt off to test it (still made noise)?
What do you think of that quote?

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Are you saying you ran the engine with the alternator drive belt removed completely and the noise was still there ????
And did you remove the air conditioning drive belt the smaller of the two?? if not then it could be the air con pump!!!!

Originally Posted by 645/333

Are you saying you ran the engine with the alternator drive belt removed completely and the noise was still there ????
And did you remove the air conditioning drive belt the smaller of the two?? if not then it could be the air con pump!!!!

Yeah the engine was in idle with the drive belt removed and was still makin the noise but actually, I didnt remove the a/c belt because I didnt have the tool to take it off. So maybe it is the a/c pump? Ugh!

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Seriously buy a mechanics stethoscope will save you a lots of money time and aggravation for a just a couple of dollars, they have extensions for longer distances, this will narrow dramatically your search for the problem.......

Originally Posted by 645/333

Seriously buy a mechanics stethoscope will save you a lots of money time and aggravation for a just a couple of dollars, they have extensions for longer distances, this will narrow dramatically your search for the problem.......

Would that be able to reach the ac pump? Btw, do u know how much those pumps go for?

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Provided you take care using it around moving parts it should be okay, or if not from the top of the engine you could easily access from below!!!
Price of pump? sorry no idea!!

Originally Posted by CJ645Bern

Would that be able to reach the ac pump? Btw, do u know how much those pumps go for?

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Reaol OEM.com is your friend, use it. Use that to get an idea of cost and then search to compare.

Thanks for all the replies. Would the a/c work if the a/c pump was bad tho? Bcuz my a/c is fine

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Hi, we are talking bearing noise, that does not mean the part is not working, but seriously don't bounce around the engine compartment buy the right tools to assist you, will save a fortune in the long run!!!

Well I finally had it figured out. In the "crank vent case", there were these orange rubber bushings and they had holes in them (probably from normal wear and tear). I spent $50 for two new ones from the dealership and $140 for diagnosis and installation from a personal mechanic. Personally, I think its not a bad price considering the stealership would probably charge me $500 with other BS for the job. But its good to finally be driving the 6 without noises coming from the engine

Originally Posted by CJ645Bern

Well I finally had it figured out. In the "crank vent case", there were these orange rubber bushings and they had holes in them (probably from normal wear and tear). I spent $50 for two new ones from the dealership and $140 for diagnosis and installation from a personal mechanic. Personally, I think its not a bad price considering the stealership would probably charge me $500 with other BS for the job. But its good to finally be driving the 6 without noises coming from the engine

I had the same job done by an indy mechanic in GA. It cost me 489 dollars to fix.

Originally Posted by castercorey

I had the same job done by an indy mechanic in GA. It cost me 489 dollars to fix.

Jeeez what was the price breakdown for that?

Originally Posted by CJ645Bern

Jeeez what was the price breakdown for that?

I can not remember and the paperwork is at home but trust me it was mostly labor.