High pitch sound

[83EWMB]

I have a high pitch continuous sound (loud enough to hear in drivers seat with windows down) coming from the engine compartment. I doesn't seem to be from belt, fan, water pump, etc. area. It sounds like it is coming from outside front right of motor. It doesn't come on until I drive around, couple of miles, and car warms up. It sounds like it is from the area of the secondary air pump. Is this pump come on when the car warms up? Could the sound be from the VANOS in that area? Any thoughts would be appreciated.

[lapd1989]

Sounds like the pump to me...

[83EWMB]

Does the pump come on any time other than for a few minutes at start-up?

[jimoreno]

Ah that's the secondary air pump! It's hidden between the front right fender liner and the bumper (under the air filter housing but from under the car). If you need to reach it you'll have to either remove the fender liner or the front bumper (this is the easiest way). By the way, my car had the air pipe disconnected at the valve and I heard this loud blowing sound and then realized all it needed was a little push and click. Done

[Timm]

The secondary air pump should have stopped after 2 minutes - if it carries on longer than that then it's either running when it should be, or something else!

[83EWMB]

The sound doesn't start until the motor warms up, 10 minutes of driving. It sounds like it is coming from the right side of the engine. I changed the timing guide tensioner 6 months ago. Could that be causing this high pitched sound? VANOS? I'm really at a loss as to what is causing this. It doesn't sound like it is coming from the belts or pulleys, but I guess it could be. Also, I changed the water pump 6 months ago, could be that? There are no codes and starts and runs perfectly. I'll try to record the sound this weekend and post here. Thanks to all.

[kouks]

Does the noise follow engine rpm?

Does it follow speed of the car? Could be front bearings?

Does it stay constant? If it changes, when does it change?

Need more info

[83EWMB]

I think I found the problem. It appears to be the Crankcase Vent Valve. There is a loud vibration at the diaphragm vent in the back of this valve. This is a new valve changed about 6 months ago.

[lapd1989]

I think I found the problem. It appears to be the Crankcase Vent Valve. There is a loud vibration at the diaphragm vent in the back of this valve. This is a new valve changed about 6 months ago.

Check it because this can also leak oil big time

[83EWMB]

Just to be sure, the direction of air flow in the one-way valve (Part # 11611312737, # 7 in attachment) is from the front of the engine to the rear? Another way to express is the air flows into the crankcase vent valve in the rear of the manifold? Is this correct. Thanks.

[83EWMB]

After watching this video,

https://www.bing.com/videos/search?q=2001+bmw+740il+pcv+valve+replacement&&vie w=detail&mid=489B4767EC080C9B6E22489B4767EC080C9B6 E22&&FORM=VDRVRVI thought for sure I understood the problem. However, there is no difference when the oil stick is in or out, therefore not sure anymore. The sound appears to come from the back of the engine and the diaphragm area of the CVV vibrates heavily. It feels like the noise is coming from right there. In response to the previous comments, the sound is constant, starts after 5-10 minutes driving, doesn't change with engine speed or anything else. Loud enough to be heard over radio inside the car with windows up. These cars really are an interesting challenge sometimes.

[lewvirg]

place your hand over the ccv vent - sound goes away - it is bad, usually the diaphragm.

I had the howling/noise - replaced with ccv from fcp euro - went bad after 8 months, the edges had curled up. Just replaced again. I am assuming even when it says genuine bmw - or an ebay special - probably made in china. Actually didnt look for mfgr marks - my mistake.

[83EWMB]

In an effort to add to the general knowledge of this forum, I thought that I would follow-up with the resolution of this thread. As I was changing the CCV in back of the manifold, loosening hoses, T27 torx bolts, etc., I noticed that the bottom left torx bolt was loose, about 1/4 inch out. I tightened it and the other bolts, reconnected the hoses, and test drove. All noise gone. Glad it was simple fix and I know that I should have checked something like that earlier (in my defense it is very difficult to get to these bottom bolts). Thanks everyone for all of your help.