whistling engine noise

[chinaski]

My car just started to develop a whistling noise. The only noise i can compare it to is the sound an after market cold air intake whistling noise. The whistling noise is most noticeable when im accelerating and is a little noticable when im idling. I popped the hood and i think the sound is coming from around the throttle body and intake manifold but i dont know what to look for.

if anyone has any info about what i can do to fix the car, it would be greatly appreciated.

[blndweasel]

Definitely suspect an air leak.

Mine was doing something like this, and it was because the airbox snorkel clip was loose, and the hose had detached itself.

The sound could very well be coming from one of your intake hoses though, too. Are they in decent condition? Try tightening the clamps. Are they cracked and old? Consider replacement.

tbw

[chinaski]

ive inspected the intake hose and the rest of the hoses are in good shape, the previous owner use armoral on them all the time. i also checked the intake box but the sound is definately coming out around the throttle body and intake manifold.

[THAT318]

u have a vacuum leak. my car is doing the same thing right now but on a more serious note. does your car idle fine at lights? mine shakes violently and its time for me to change out any and all hoses in my bay.

[gldfshkpr]

Originally Posted by chinaski

My car just started to develop a whistling noise. The only noise i can compare it to is the sound an after market cold air intake whistling noise. The whistling noise is most noticeable when im accelerating and is a little noticable when im idling. I popped the hood and i think the sound is coming from around the throttle body and intake manifold but i dont know what to look for.

if anyone has any info about what i can do to fix the car, it would be greatly appreciated.

The bad news is this can be very serious. The good news is it's an simple fix.

First off, to troubleshoot it. Take off your oil cap and see if there's suction when you take it off. Secondly, take off the tube going from the valve cover to the little black plastic part which is a valve that lets the un-burnt gasses back into the cylinders. Forget what it's called. In any case, the valve costs $80 and could be bad. Mine was stuck closed, causing too much pressure in the engine.

I'm real tired today after completing my starter install today. Let me know how the trouble shooting goes.

[Keir]

Originally Posted by gldfshkpr

The bad news is this can be very serious. The good news is it's an simple fix.

First off, to troubleshoot it. Take off your oil cap and see if there's suction when you take it off. Secondly, take off the tube going from the valve cover to the little black plastic part which is a valve that lets the un-burnt gasses back into the cylinders. Forget what it's called. In any case, the valve costs $80 and could be bad. Mine was stuck closed, causing too much pressure in the engine.

So if there is suction when taking the oil filler cap off is the valve working correctly?

[tiFreak]

Originally Posted by Keir

So if there is suction when taking the oil filler cap off is the valve working correctly?

there should be suction and the engine will start running badly until you put the cap back on

[gldfshkpr]

Here's the deal. If there is TOO much pressure. Not good. If you have to struggle to get the cap off like a jar of tomato sauce, it's too tight. That's an indicator your breather valve is stuck.

Edit. Any chance you can get a video of this sound / happening.

[d2007k]

my old car whistled a tad when the head gasket started to go

[xxxJohnBoyxxx]

Dangerous so be careful.

Grab fire extingusher and flamable carb spray. Start car and spray carb spray where you think you have the air leak. The engine will idle higher or stumble and try to stall when you find your leak.

Do not spray on exhaust, electronics like alternator or areas that may ignite the carb spray. No smoking...You have been warned

Did I say be careful

[kaamacat]

I have exactly the same issue on our 97ti. When I pulled the oilcap off (and it was a somewhat forced pull) the noise immediately stopped, engine ran rougher as expected, so onward for a new valve. (EXCELLENT POST AND THANKS).

I may pull it off and see if it can be "un-stuck/cleaned", but still a new valve is in order.

[huckaboo]

by taking off the oil cap with the engine running you are testing the PCV (positive crankcase ventilation) if you take it off and have a small amount of suction and the engine starts to run rough it is most likely stuck open. stuck closed would cause your car to have a pretty rough idle all the time. my car has a slight rough idle all the time but its not very noticeable. the part you need is on pelicanparts.com -

http://www.pelicanparts.com/cgi-bin/...C%20Each%20%20

[kaamacat]

Stupid me ordered the flange 1st (ehh it was messed up anyway with oil and broken pcv parts).....For some reason I was thinking it was all one unit...WRONG.

In the pics it is the Crank Case Vent Valve (which strange enough is more expensive than the nicely machined flange). When looking at a BMW parts picture it is NOT in the pics with the intake and the flange between the upper/lower but rather in the pics of the valve cover itself at the end of the joined water/pcv tube.

So long-story-short, replacing the CCVV did the trick, and, could have just removed it with the two hex bolts from the underside of the flange. (no biggie).

[Bonez21]

I found the answer helpful, even after so many years. After looking for the location of the noise and the threads in this I realized it was the CCV. I ordered it already.

Thanks to all of you