loud noise from engine - BMW Forum

05lcBMW · 08-19-2009, 03:08 PM

after a while of driving, the engine makes a loud high pitch whining noise. it only does it when i decelerate and when im at a stop. as soon as a accelerate the noise goes away. i put wd-40 on everything that rotates and the noise continues. does anyone have any suggestion?

witeshark · 08-19-2009, 03:10 PM

You may be on the hunt for a vacuum leak.

05lcBMW · 08-19-2009, 03:21 PM

any suggestions as to where to look?

witeshark · 08-19-2009, 03:24 PM

It really depends on the individual car. Maybe a look at realoem.com can help

darkhorse737 · 08-19-2009, 03:36 PM

Quote:

Originally Posted by 05lcBMW

after a while of driving, the engine makes a loud high pitch whining noise. it only does it when i decelerate and when im at a stop. as soon as a accelerate the noise goes away. i put wd-40 on everything that rotates and the noise continues. does anyone have any suggestion?

try WD-40 on the belts. still there?

A whine is always the effect of a pulley bearing gone bad. More so if the pitch of the whine changes as u accelerate or decelerate.

Contrast that to a "whistling" noise which is attributed to intake leaks.

What about when you are stationary(not moving) and u rev the engine... still there? You can go further by listening where the nois is greatest. that will help. :-)

05lcBMW · 08-20-2009, 02:01 AM

yeah its a whistling noise. i did a a test where i warn um the car and take the engine oil cap off to see if the engine wants to turn off and it did want to turm off. so more than likely its a vacuum leak.

darkhorse737 · 08-20-2009, 02:08 AM

easy!

get ur self a can of brake cleaner. run engine at idle and start spraying sparingly at every place there you suspect a leak...

when u notice a change in idle as u are spraying... the point when the idle drops is also where the intake leak is ;-)

shope charge as much as $85.- do do dx like that.. I give my tips for FREE ;-)

Cheers

05lcBMW · 08-20-2009, 03:03 AM

thanks for your help.